HCMC UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY OF MECHANICAL ENGINEERING REPORT ADVANCED MECHANICAL MEASURING EXPERIMENT TEACHER Đặng Minh Phụng . Toàn bộ tài liệu được viết bằng tiếng anh do Thầy Đặng Minh Phụng hướng dẫn. Nếu các bạn không biết bắt đầu từ đâu do khối lượng công việc Thầy giao quá nhiều thì đây là tài liệu rất có ích cho bạn.
Structure of CMM
CMM coordinate measuring machine consists of 4 main parts:
Classification of several types of CMM meters by structure
Classification of CMM machines by structure, there are several types of machines as follows:
- Folding hand gauge: usually a small hand-held machine Allows the swivel head to be placed in different directions
The X-axis bridge gauge features a measuring shaft mounted vertically and a horizontal girder supported on two piers This setup provides stable, high-precision measurement by creating a rigid reference plane for the product to be measured By expanding the measuring range along the X-axis, the gauge can accommodate larger parts and improve throughput in dimensional inspection Overall, this bridge gauge design enhances measurement range and accuracy for a variety of applications.
- Key gauge: with the measuring shaft supported by a shaft-supporting structure
Truss gauges are measurement devices featuring a frame structure that hangs on piers, enabling the measuring range to extend over the objects being measured Structurally, truss gauges are similar to bridge gauges, sharing the same design principles and construction.
- Horizontal type gauge: machine with a protruding transducer shaft One end is attached to a movable vertical support
Classification of several types of CMM meters by control system
- Manual CMM series: manual drive
- Motor driven CMM series with automatic detection
- The CMM series of meters are controlled directly by the computer
- The CMM series of meters are linked with CAD, CAM, FMS.
Application of CMM
- -CMM machine gradually becomes the main equipment for product quality inspection Due to the product processing shape becomes more and more complex, the precision is high
- -It is used to check the machined dimension To ensure the supply of qualified products for the next working process
- -In each processing process, when there is a change of state, it should be sent to the 3-D measuring machine CMM For example tool replacement, machining time or program
For extremely complex mechanical parts, traditional equipment often fails to meet stringent quality-control requirements, while the design and fabrication of the measuring devices themselves become challenging due to the intricacy of the manufacturing process As a result, coordinate measuring machines (CMMs) have become the primary tool for quality control in modern manufacturing, enabling precise measurement and verification where conventional methods fall short.
- -The same goes for modern CNC machines, so using a CMM to check machining accuracy is a necessity
- -Understand the tuning status of the device
When CMM measurement results show that part dimensions are deflected toward one side of the tolerance zone, it indicates the equipment is not delivering optimal performance This deviation signals operators to adjust the machinery as needed to bring the process back into specification, improving precision, quality control, and reducing waste in manufacturing.
Using CMM gauges enables substantial cost savings in production by reducing product errors and strengthening quality control When combined with precision-machined parts, these measurements ensure compatibility with other components, enabling seamless assembly and the efficient production of finished products.
VMM
What is a VMM machine?
An optical vision measuring machine (VMM) is a coordinate metrology device that uses machine vision to measure linear dimensions and geometric sizes with high accuracy in computer technology applications By integrating precision optics, high-resolution imaging sensors, and calibrated coordinates, the VMM delivers repeatable, non-contact dimensional analysis for quality control and manufacturing processes This setup enables fast inspections and reliable measurements, making the VMM a versatile tool for precision engineering in electronics, optics, and other tech-driven industries.
Structure of VMM
2D measuring machines (VMMs) generally have 3 main blocks:
Classification of VMM machine
VMM machines are offered in cantilever and bridge configurations to suit different workflows: the cantilever type is available for manual and semi-auto VMM, and also for economical, small-size automatic VMM, with dimensions under 500 x 400 x 300 mm For bridge-type VMMs, there are two variants: mobile-bridge and fixed-bridge, providing both mobility and stable support options.
Application OF VMN machine
High precision with fixed workbench and granite base
RS-232 interface can communicate between measurement software and computer Users can manage and export charts in BMP and DWG formats by connecting to a
PC and running the program
It can measure linear dimensions.
Advantage OF VMM machine
Advantages vision measuring machine achieves high accuracy of micrometer (0.001mm)
A 3D measuring machine with an integrated touch probe offers a cost-effective, easy-to-use solution that requires no complex installation and no highly skilled operators like traditional CMMs With high-resolution cameras, strong magnification, and image-processing measurement software, it enables precise measurements of very small features, including objects under 1 mm.
3D PRINTING
What is 3D Printing
3D printing or additive manufacturing is a process of making three dimensional solid objects from a digital file
3D printing, or additive manufacturing, builds objects by laying down successive layers of material until the final item is formed In this approach, each layer acts as a thin cross-section of the completed object, and by stacking these layers—one atop another—the full 3D model emerges.
3D printing is the opposite of subtractive manufacturing which is cutting out / hollowing out a piece of metal or plastic with for instance a milling machine
3D printing enables you to produce complex shapes using less material than traditional manufacturing methods.
How Does 3D Printing Work
It all starts with a 3D model You can opt to create one from the ground up or download it from a 3D library
There are many different software tools available From industrial grade to open source We’ve created an overview on our 3D software page
For beginners, we often recommend Tinkercad, the free, browser-based 3D design tool that runs directly in your web browser with no installation required It offers beginner-friendly lessons and includes a built-in export feature to save your model as printable STL or OBJ files.
Now that you have a printable file, the next step is to prepare it for your 3D printer This is called slicing
Slicing: From printable file to 3D Printer
Slicing basically means slicing up a 3D model into hundreds or thousands of layers and is done with slicing software
Once your model is sliced, the file is ready for the 3D printer You can feed the sliced file to the printer via USB, SD card, or Wi‑Fi With the file loaded, the printer will fabricate your object layer by layer, turning a digital design into a physical model.
3D printing adoption has reached critical mass, with additive manufacturing becoming a standard part of modern supply chains as the number of holdouts shrinks What started as a solution for prototyping and one-off manufacturing is rapidly evolving into a full-fledged production technology, enabling scalable, on‑demand production and transforming manufacturing operations across industries.
5 and Consulting forecasts the global 3D printing market to reach $41 billion by 2026
As it evolves, 3D printing technology is destined to transform almost every major industry and change the way we live, work, and play in the future.
Examples of 3D Printing
3D printing, also known as additive manufacturing, spans a broad range of technologies and materials and is now deployed across virtually every industry To fully leverage its potential, it should be understood as a cluster of diverse sectors, each offering a wide array of applications and benefits.
– consumer products (eyewear, footwear, design, furniture)
– industrial products (manufacturing tools, prototypes, functional end-use parts)
– reconstructing evidence in forensic pathology
Automotive manufacturers have long used 3D printing (additive manufacturing) to produce spare parts, tools, jigs, and fixtures, and increasingly to manufacture end-use parts This approach enables on-demand production, reducing stock levels and shortening design and production cycles, which accelerates time-to-market and enhances supply-chain flexibility in the automotive industry.
Automotive enthusiasts around the world are using 3D-printed parts to restore vintage cars, with additive manufacturing enabling new life for classic machines A notable example comes from Australian engineers who printed components to bring a Delage Type-C back to life, including parts that had been out of production for decades This demonstrates how modern 3D printing can unlock restoration projects by providing precise, obsolete parts that are no longer commercially available.
3D printing is transforming aviation by enabling critical components to be manufactured additively, with GE Aviation marking a landmark milestone by 3D printing 30,000 cobalt-chrome fuel nozzles for its LEAP engines Achieved in October 2018, this feat demonstrated the power of additive manufacturing in aerospace, and with about 600 nozzles produced each week on forty 3D printers, production capacity has likely continued to grow since then.
Twenty parts that were previously welded together have been consolidated into a single 3D-printed component that is 25% lighter and five times stronger The LEAP engine remains the best-selling engine in the aerospace industry thanks to its high efficiency, with GE saving about $3 million per aircraft by 3D-printing the fuel nozzles This single 3D-printed part drives hundreds of millions of dollars in financial benefit by boosting performance, reducing weight, and lowering manufacturing costs.
GE’s fuel nozzles have made their way into the Boeing 787 Dreamliner, and 3D-printed parts aren’t limited to the nozzle The aircraft also features 33-centimeter-long structural fittings that secure the aft kitchen galley to the airframe, printed by Norsk Titanium Norsk Titanium chose titanium for its very high strength-to-weight ratio and because its higher material cost makes the waste reductions enabled by additive manufacturing especially financially meaningful The company’s use of 3D printing reduces material waste compared with traditional manufacturing, delivering lightweight, durable components for the 787.
Rapid Plasma Deposition, a form of Directed Energy Deposition that uses titanium wire, can deposit up to 10 kg of titanium per hour For a 2 kg titanium part, conventional machining from a 30 kg billet would generate about 28 kg of waste, while additive manufacturing with titanium wire would require only about 6 kg of material to print the same part, illustrating the substantial material waste reduction achievable with titanium wire deposition.
Is it possible to print a building? – yes it is 3D printed houses are already commercially available Some companies print parts prefab and others do it on-site
Most articles on this site focus on large-scale 3D concrete printing systems with big nozzles and high flow rates, which are great for rapid, repeatable layer deposition However, truly intricate concrete work that fully leverages the capabilities of 3D printing requires a solution that is more nimble and offers a finer touch, delivering the precision and control needed to craft complex geometries.
Since we started blogging about 3D printing in 2011, the technology has evolved from a niche prototyping tool into a viable production method for high-volume manufacturing Today, there are numerous examples of end-use, 3D-printed consumer products across industries, proving that additive manufacturing can scale from concept to mass production This evolution highlights how 3D printing enables faster prototyping, customization, and on-demand production for consumer goods.
Adidas' 4D range showcases a fully 3D-printed midsole, manufactured in large volumes to scale production Earlier coverage noted that Adidas initially released only 5,000 pairs to the public and aimed to sell 100,000 pairs of their AM-infused designs by 2018.
With their latest iterations, the shoe line appears to have surpassed the target—or at least be on track to do so These sneakers are available worldwide, stocked in Adidas stores and through a range of third-party online outlets.
The 3D printed eyewear market is projected to reach $3.4 billion by 2028, with the end-use frames segment expanding rapidly 3D printing offers a particularly suitable production method for eyewear frames, since individual measurements can be readily translated into a precise, customized end product This enables faster customization, improved fit, and scalable manufacturing for personalized eyewear.
3D printed ophthalmic lenses are now a reality: traditional glass lenses are cut from large blanks, wasting about 80% of the material and forcing labs to hold massive blank inventories to meet individual vision needs By replacing stock blanks with on‑demand manufacturing, 3D printing cuts waste and inventory costs while delivering high‑quality, custom ophthalmic lenses The Luxexcel VisionEngine 3D printer uses a UV‑curable acrylate monomer to produce two pairs per hour with no polishing or post‑processing, and is capable of creating lenses with different focal regions—one area for improved distance vision and another for clearer near vision.
Jewelry production with a 3D printer occurs in two main modes: direct and indirect manufacturing In direct 3D printing, the item is produced as a finished piece straight from the digital design, bypassing molds or patterns In indirect manufacturing, the 3D-printed object serves as a pattern that is used to create a mold for investment casting, which ultimately yields the final metal jewelry.
Headlines about 3D printed implants often portray the technology as experimental, which can make 3D printing seem like a fringe option in medicine But this isn't the case anymore—3D printing is a mainstream capability in the healthcare sector Over the last decade, GE Additive has 3D printed more than 100,000 hip replacements, illustrating the widespread adoption of 3D printed implants in orthopedic care.
Types of 3D Printing Technologies and Processes
The American Society for Testing and Materials (ASTM), developed a set of standards that classify additive manufacturing processes into 7 categories These are:
Stereolithography (SLA) Digital Light Processing (DLP) Continuous Liquid Interface Production (CLIP)
Fused Deposition Modeling (FDM) Fused Filament Fabrication (FFF)
Multi Jet Fusion (MJF) Selective Laser Sintering (SLS) Direct Metal Laser Sintering (DMLS)
3D-SCANING
Introduction
3D scanning provides a practical way to start a 3D printing project by turning a real object into a precise digital replica You can build a three‑dimensional model from scratch with 3D modeling software, or use a 3D scanning workflow to capture the object's geometry directly If you’re curious about this 3D method, this blog post explains how it works and what you need to get started with 3D scanning for your next print.
What is 3D scanning, how does it work and how can this be used for 3D printing? Let’s find out.
What is 3D scanning
3D scanning analyzes real-world objects to capture data that digitally recreates their shape and appearance, turning them into 3D models that can serve as a base for your projects or as tools to reconstruct, analyze, or simulate ideas There are several ways to create a digital version of a real object, with laser 3D scanning, photogrammetry, and structured light scanning standing out as the main methods, each offering different workflows and capabilities The best technique for your project depends on its context and requirements, including accuracy, object size, material, and budget.
How does 3D scanning work
Laser 3D scanning is the most common and widely used 3D scanning technique, digitally capturing the shape of an object with laser light to produce a precise digital representation of the real object These 3D scanners can measure extremely fine details and accurately capture free-form shapes, generating highly detailed point clouds for a wide range of applications.
This laser scanning technique is perfect for measurement and inspection of complex geometries It allows getting measurements and data from where it is impractical with traditional methods!
A laser-based scanner works like a camera in that it can only capture what lies within its field of view In this process, a laser dot or line is projected onto the object from the device, and a sensor measures the distance from the scanner to the object's surface.
By processing this data, it can be converted into a triangulated mesh, and then a CAD model
Photogrammetry is the science of taking measurements from photographs, using parallax between images captured from different viewpoints This approach can record complex 2D and 3D motion fields and mirrors the stereo vision of the human eye, providing rich information about existing objects By analyzing the data, photogrammetry determines the shape, volume, and depth of the subject being scanned, turning photographic data into precise spatial measurements.
Transforming multiple photos into an accurate 3D design is done through a photogrammetry workflow While no method guarantees perfect precision, using high-quality photogrammetry software can produce a highly satisfying, accurate 3D model suitable for visualization, analysis, or prototyping.
Structured light scanning replaces one of the traditional camera positions with a projector that projects varying light patterns onto the surface of an object, and by capturing how these patterns are distorted by the object's geometry, the system analyzes the distortions to generate a precise 3D scan.
The structured light scanning process is used in facial or environment recognition technologies.
How to use 3D scanning
3D scanning offers a faster, easier way to create a 3D model for 3D printing when you simply want to reproduce an existing object Once you have the model, you can add modifications, making it a strong foundation to start and customize your project.
3D scans are transforming healthcare by enabling patient-specific prostheses to be designed and produced directly from digital scans, improving accuracy across medical specialties In dentistry, 3D scanning is widely used to observe anatomy, simulate treatment options, and fabricate devices like braces, implants, and dentures By pairing 3D scanning with 3D printing, practitioners can avoid the drawbacks of traditional molds and streamline the entire fabrication process for medical prostheses and dental appliances.
3D scanning offers numerous benefits, especially the ability to store precise digital records that can be reused in future projects These digital assets enable accurate measurements, simulations, and restoration planning, helping save time and costs while reducing risk For example, 3D scans of Notre-Dame Cathedral in Paris, which partially burned on April 15, 2019, could be used to guide its restoration by providing faithful geometric data and reference models This technology holds tremendous potential for heritage preservation, architecture, and urban planning, enabling archivists, designers, and restoration teams to archive, study, and reconstruct complex structures.
This article clarifies how 3D scanning techniques work and what each method can offer for capturing real-world objects Are you already using any of these 3D scanning methods? Let us know your experience in the comments If you're exploring 3D scanning, check out our guide to the best 3D scanners to determine which model could best support your project.
DIAL GAUGE
Structure
Dial gauge is a common indicator used in test measuring instruments to indicate the deviation of a measurement
Is a device used to measure straightness, end segment, inner radial segment, measure parallelism of grooves
19 usually made of wear-resistant alloy
- Spindle: depending on the type of meter, there are different lengths, to meet the inspection of specific types of details, the measuring axis has a reciprocating movement along the bushing
- Stern: guide and protect part of the measuring shaft
Drive mechanism consists of transmission linkages that drive the measuring shaft and translate its motion into the movement of hands on an analog counter-dial, displaying the results; for a digital-display odometer, a system of sensors and electronic circuits processes the measured data from the measuring head.
- Outer frame: helps protect the internals of the gauges, can also be water resistant for some gauges
➔ There are also caps, locking screws, clamping levers and some other extra parts depending on the design of the dial
Although the overall design is simple, there are many variations in design details, style, and test function across different models When classifying these devices, two main types emerge: mechanical and electronic.
Mechanical watches, the whole system of counting and displaying measurement results is mechanical, the display faces are divided by clockwise This category includes the following categories:
This precision gauge features a movable measuring head and a measuring axis that can be raised or lowered, allowing fine vertical adjustment for accurate measurements It offers selectable resolutions of 0.01 mm, 0.001 mm, 0.002 mm, and 0.005 mm, with measurement ranges of 0–1 mm, 1–5 mm, or 1–10 mm.
This odometer is often referred to as a separate mechanical chronometer due to its special structure in the measuring shaft Folding leg gauges, also known as lame gauges, apply the principle of lever resonance to amplify the movement of the transducer The measuring head is compact and the measuring angle can be adjusted freely Thanks to this flexibility, the folding foot gauge is used for measuring positions in small spaces that are difficult to access with conventional gauges.
➢ Horizontal retaining bar dial gauge
This meter displays the measurement on the back of the meter's display and features a horizontal retaining bar, designed for situations where readings are difficult to read with a standard gauge type.
This dial-type meter offers a wide measuring range from 20 mm to 100 mm with a 0.01 mm division, ensuring precise readings across the span It features a substantially larger dial than standard models and a longer measuring axis, which improves visibility and measurement accuracy.
An electronic comparator processes measured data through electronic sensors and displays the results as decimal numbers on an LCD screen Because it is not dependent on the internal mechanical structure or the length of the measuring shaft, electronic counters are designed in many neat configurations As a result, an electronic comparator model can be suitable for a wide range of test conditions.
Appliactions of dial gauge
- Comparing two heights or distances
- It is used to measure the deformation such as in tension or compression
- To check the errors in geometrical form such as ovality, roundness, run out, and taper
- It is used to measure pit depth in EDM (Electric Discharge Machine)
- It is used to measure surface roughness
- It is used to determine the potential errors of surfaces such as parallelism and alignment
- Used to align job in lathe centers
- It is used to check the trueness of the milling machine
- Size of the dial gauge is very small and compact, so it can be used easily in mass production
- Dial gauges can be used to measure the amount of tapper in round objects easily
- It is the most flawless tool in taking linear measurements
- The precision of the dial gauge is often lost due to the vibration of machinery
- The main disadvantage of the dial gauge is parallax error
Parallax error occurs when the measured length of an object differs from its true length because the observer’s eye is positioned at an angle to the measurement markings This optical discrepancy arises from misalignment between the line of sight and the scale, causing readings to appear longer or shorter than the actual size To minimize parallax error, align your eye directly with the markings and view the measurement at a perpendicular angle.
- Due to space constraints the tool is needed to be installed at an angle due to which the accuracy of the device is lost.
How to use dial gauge
This is a guide on how to use the dial in general, not all cases are the same, but the basic usage and measurement methods will be as follows
Determine the object to be measured, the space to carry out the measurement, select the appropriate meter and the attached stand
Check that the dial gauge is intact and in good working order
Fix the dial and the object to be measured on the bracket, adjust the scale to 0 and prepare to measure
Position the object to be measured in contact with the odometer's measuring head and read the value from the pointer or the LCD display For the most accurate results, perform the measurement 2–3 times.
To read a mechanical odometer, start with the small-scale ruler and its index needle (the short hand) to determine the integer millimeters: when the short needle aligns with a single mark, the measuring head has moved 1 mm The decimal portion is read from the large-scale dial using the long index hand (the long hand) If the scale is graduated in 0.01 mm increments, read the small-scale value as 1 and the large-scale value as 26, giving a total measurement of 1.26 mm.
When you understand what the principle of the clock is Then we can learn how to use the odometer easily Here are the most basic uses of the meter:
Specify the measurement space, select the dial gauge, select the measuring location, and the measuring object
If using a mechanical dial We should check the hands of the watch to make sure that the counters are still in good working order
Identify the object to be measured, lock the dials in place, and set the scale to zero Then adjust the contact position of the measuring instrument against the object to ensure proper alignment, and read the measurement directly from the dial for an accurate, repeatable result.
To set the meter, adjust its position according to the location of the measuring piece The measuring rod should be placed perpendicular to the measuring surface to ensure accurate readings.
Reading millimeters on this gauge is straightforward: the ring index needle on the ruler determines integer millimeter values, so when the needle points to 1, the gauge reads 1 mm For percent millimeter readings, interpret the value from the needle on the large-scale dial.
In addition, with the electronic comparator, the measured value is displayed in direct digital form and the reading of the measured value becomes very simple
How to use the meter correctly?
Step 2: Place the meter on the multimeter holder or separate accessory and adjust the position of the meter to suit the position of the part to be measured, making sure the measuring rod is placed perpendicular to the measuring surface
Step 3: Refine the clock to make sure it's still in good working order
Step 4: Fix the meter relative to the objects to be measured on the bracket and adjust the large dial to the right "0" position for the hand and perform measurement
Step 5: Adjust the object to be measured in contact with the measuring head of the meter and then read the value of the pointer or the value on the dial
To ensure highly accurate results, it is recommended that you perform the measurement from 1 to 3 times
How to read meter value
Millimeter values are read from the circular index needle on the small scale, while the corresponding millimeter percentages are read from the pointer on the larger scale Each increment of one mark on the needle causes the gauge bar to move by 1 mm.
For electronic comparators, the measured value is displayed in digital form on the screen, so reading the results becomes much simpler
Methods of measuring with a dial gauge
This is a widely used measuring method that is ideal for parts whose dimensions exceed the instrument's measurement range, and it is also employed to test a variety of components to speed up inspections and quality checks.
Measurement by comparison is performed by clamping the gauge to the mounting base and setting it to a sample block whose size matches the nominal size of the part to be examined Then the sample block is replaced with the actual part to be checked, and the deviation is read from the dial, with both the sign and the magnitude indicating the degree of deviation.
Place the measuring head in contact with the map table, set the dial gauge to zero, then insert the part to be measured—the dial gauge reading will indicate the part's absolute size.
➢ Examples of some metering applications
Measure runout is the largest difference between the values of the meter compared to when the part rotates 1 revolution
To check flatness and parallelism, place the measuring head on the surface of the part, move the sliding component across the table, and observe changes in the meter’s index to determine the result.
How to maintain dial gauge
After use, the clock should be checked for any damage, if any, it needs to be repaired
If there is no problem, it should be cleaned with a special soft cloth or paper
Never use lubricating oil on the gauge head
For electronic counters, if not used for a long time, the batteries should be removed before storing
When storing, the meter should be covered with the dust cover provided, placed in the carrying case and stored in a dry place
❖ Some accessories that come with the watch
To must be used and ensure the results of is precision, must have a few accessories that come with the watch, including:
Tip table: is a granite loading pole, use the setting base and object to be measured Dial holders: There are many types of holders, for fixed use of the dials
Standard sample bases: use standard size settings
Calibration meter instrument: adjust the accuracy of the clock after a period of use
Designed for shop-floor use and mobile measurement, this handheld surface roughness tester combines simple operation with fast, accurate, and stable readings and easy handling It is suitable for production sites and can measure the surface roughness of a wide range of machined parts The tester evaluates surface textures using multiple parameters in accordance with national and international standards Results are displayed digitally or graphically on an OLED screen and can be printed directly With various gauge types and a similar construction, this handheld instrument represents portable roughness measurement devices.
+ Electromechanical integration design, small size, light weight, easy to operation;
+ 20 parameters:Ra, Rz, Rq, Rt, Rp, Rv, R3z, R3y, Rz(JIS), Rs, Rsk, Rsm, Rku,Rmr;
Ry(JIS)=Rz, Rmax=Rt, RPc, Rk, Rpk, Rvk, Mr1,Mr2
+ Display full information, intuitive and graphical displays all parameters; + Compatible with ISO1997, DIN, ANSI, JIS2001 multiple national standards; + 4 Profile Filter: Gauss RC PC-RC DP
+ Large capacity data storage, can store 100 item of raw data and waveforms; + Can connected to the computer and printer；
+ All parameters can be printed or print any of the parameters which set by the user；
To measure surface roughness, the pickup is placed on the part surface and traced at a constant rate The sharp stylus in the pickup interacts with the surface texture, causing displacement that changes the inductive value of the coils and generates an analog signal proportional to the surface roughness at the output of the phase-sensitive rectifier This signal is fed into the data acquisition system after amplification and level conversion The collected data are then processed by a DSP chip using digital filtering and parameter calculation, and the measured results can be read on the OLED display, printed through a printer, or transmitted to a PC.
When the surface to be measured is smaller than the instrument’s bottom surface, the pickup sheath and the instrument’s adjustable supports can be used as auxiliary supports to complete the measurement, as illustrated in the figure.
A measurement stand enables convenient adjustment of the tester-to-part position with flexible, stable operation and a wide application range It can measure the roughness of complex shapes while allowing precise stylus positioning to enhance measurement stability For surfaces with relatively low Ra values, using a measurement platform is recommended.
Extending rod increases the depth for pickup to enter the part Length of extending rod is 50mm
Most standard surface roughness sensors can measure roughness on a wide range of geometries, including flat planes, inclined planes, cone surfaces, internal holes, and grooves, and they can be used for handheld measurements Beyond these standard sensors, some measuring platforms require specialized sensors to achieve accurate surface roughness measurements.
Curved surface sensor is mainly used for measuring radius is larger than the smooth cylindrical
3mm surface roughness, for the larger radius smooth spherical surface and other surface
34 also can obtain good approximation, the radius of curvature, the surface is smooth, the better the effect of measurement
Using Pinhole pickup, the inner surfaces of holes with radius more than 2mm can be measured
Refer to the following Figure for detailed dimension
Using a deep groove sensor, you can measure grooves wider than 3 mm and deeper than 10 mm, and assess the surface roughness of steps with heights under 10 mm.
Also can used to measure the planar, cylindrical used with platform please see figure for detailed dimension
Measurement principile
Surface roughness is measured by moving a pickup, equipped with a sharp stylus, across the part surface at a constant speed The stylus deflection caused by surface texture changes the inductive value of the pickup’s coils, producing an analog signal proportional to roughness at the phase‑sensitive rectifier output This signal is amplified, level‑shifted, and fed into the data acquisition system, where digital filtering and parameter calculation are performed by a DSP chip The resulting measurement can be viewed on an OLED display, printed via a printer, or transmitted to a PC for further analysis.
Genel structure
Options and usages
If the surface to be measured is smaller than the instrument’s bottom surface, the pickup sheath and the instrument’s adjustable support options can be used as auxiliary supports to complete the measurement, as illustrated in the figure.
The measurement stand allows convenient adjustment of the distance between the tester and the part being measured, delivering flexible, stable operation and a wider application range It can also measure the roughness of complex shapes, and it enables precise positioning of the stylus for more stable, accurate readings For surfaces with relatively low Ra values, using a measurement platform is recommended.
Extending rod increases the depth for pickup to enter the part Length of extending rod is 50mm
Most standard surface-roughness sensors can measure roughness on a variety of geometries, including flat planes, inclined planes, conical surfaces, inner holes, and grooves They are handheld, enabling convenient, on-site measurements For some geometries or applications, standard sensors must be complemented by special sensors, and a suitable measurement platform may be required to obtain accurate results.
Curved surface sensor is mainly used for measuring radius is larger than the smooth cylindrical
3mm surface roughness, for the larger radius smooth spherical surface and other surface
34 also can obtain good approximation, the radius of curvature, the surface is smooth, the better the effect of measurement
Using Pinhole pickup, the inner surfaces of holes with radius more than 2mm can be measured
Refer to the following Figure for detailed dimension
With a deep groove sensor, grooves wider than 3 mm and deeper than 10 mm can be measured, and the sensor can also assess the surface roughness of steps whose height is under 10 mm, enabling precise dimensional and surface quality analysis for small-feature components.
Also can used to measure the planar, cylindrical used with platform please see figure for detailed dimension
CALIPER
Structure of caliper
The caliper consists of a Vernier caliper, a main scale (ruler), a holding knob, and a clamping jaw The main body or frame carries a long scale divided in centimeters, with the smallest division at 1 millimeter The Vernier scale is smaller than the main scale and contains up to 50 divisions for finer measurements Together, these components provide precise linear measurements.
In a vernier caliper, the main base is the central component to which all other parts—such as the sliding scale, jaws, and locking mechanisms—are attached It functions as the instrument’s foundation, providing a stable reference surface that sustains alignment and rigidity, which in turn supports accurate measurements In short, the main base underpins the caliper’s structure and measurement reliability.
The main scale serves as the primary reference for reading measurement results, acting as the starting point from which measurements are interpreted In practical use, the main scale is typically expressed in centimeters, providing a standardized unit for precise and comparable measurements.
Taking measurements with a caliper begins with reading the main scale, but its accuracy is limited to about 1 mm To achieve higher precision, you must consult the vernier scale as well, because the vernier reading refines the measurement beyond the main scale By aligning the zero on the vernier with the main scale and selecting the vernier line that best matches, you obtain a measurement accurate to a fraction of a millimeter This combined approach yields more reliable caliper results and minimizes measurement errors.
37 scales, namely the units of cm and inches In this article, the caliper in the picture contains only one unit
The vernier scale, also known as the nonius scale, is the secondary reading that complements the main scale Start by reading the main scale to establish the integer part of the measurement, then use the vernier scale to obtain the decimal value, providing an accuracy of up to 0.1 mm Both scales must be read together and in the correct order, and the vernier reading is obtained only after the main scale has been read.
Like the main scale, calipers feature additional vernier scales that come in two unit types: millimeters (mm) and inches The unit choice is up to the user, so measurements can be read in either mm or inches according to preference.
A caliper’s slider is the moving component that drives the jaws to widen or narrow, allowing precise measurement of an object’s dimensions The slider sits directly on the main base and carries a nonius (vernier) scale, enabling accurate readings when measuring with the caliper.
In the image, the finger hook is a semicircular piece connected to the slider, creating a grip area to move the slider This section is designed for easy one-finger operation, allowing you to rotate the finger hook with your thumb to shift the slider smoothly.
The lock screw secures the slider after it has been shifted to match the object's size, preventing any movement and ensuring an accurate reading The fixed inner jaw provides stable, precise contact, reinforcing measurement reliability and repeatability.
Rahang dalam tetap adalah bagian rahang yang terletak pada tempatnya, yang tidak dapat digerakkan karena menyatu dengan main base Fungsi rahang ini adalah untuk mengukur diamater dalam suatu benda
A sliding inner jaw is a jaw that can be shifted according to the size of the object This jaw is attached to the slider so that it can be shifted wider and narrower for measurement needs The sliding inner jaw works to measure the inner diameter of an object This jaw works in conjunction with the fixed inner jaw
The fixed outer jaw remains attached to the main case along with the fixed inner jaw
This jaw serves to measure the outer diameter of an object
Similar to the moveable inner jaw, the moveable outer jaw is a jaw that can be shifted wider and narrower for measurement purposes This jaw serves to measure the outer diameter of an object that works in conjunction with a fixed outer jaw
The depth rod is a long rod embedded in the main housing, with only its ends visible in the image, and it is directly connected to the slider so that moving the slider also changes the depth rod position.
With the jaw closed, the slider moves toward the fixed jaw, exposing only the edges as shown When the jaw is opened, the depth rod becomes more visible, and the wider the opening, the longer the depth rod appears The depth rod is used to measure the depth of hollow objects or tubes.
Understanding the components of a caliper is essential for anyone who uses this precision measuring tool regularly, because each part—such as the jaws, the slider, and the scale or digital readout—has a specific function, and misinterpreting how any component works can introduce measurement errors and compromise accuracy.
Caliper components are not always identical across different caliper models Because there are various caliper designs, you may encounter slight differences in the names of the components depending on the specific type of caliper.
Working of priciple caliper
Principle Of Working Of Vernier Scale
The vernier scale works by using the alignment of slightly offset line segments to enable fine measurements, a result the human eye can easily detect and use to read the scale A vernier caliper consists of a main scale and a vernier scale; the main scale provides a baseline resolution of 1 mm, while the vernier scale is attached to and can slide along the main scale with its graduations spaced by 1 mm but displaced by 0.1 mm relative to the corresponding main-scale marks This deliberate displacement is the key to increased precision When the vernier is at zero, the zeros on both scales coincide; as you slide, the first vernier mark sits 0.1 mm short of the first main-scale mark, the second 0.2 mm short, and so on up to the tenth mark, which is 1.0 mm short of its main-scale counterpart The measurement is read by identifying which vernier division aligns with a main-scale division and then adding that vernier offset to the main-scale reading, yielding a precise result with a least count of 0.1 mm while the main scale provides the gross reading.
MICROMETER
What is a Micrometer
A micrometer is a highly precise measuring instrument widely used in mechanical manufacturing and materials processing to accurately measure the thickness of a block, the outer and inner diameters of shafts, and the depth of slots, with common applications across plastics, wood, aluminum, and glass.
A micrometer is a device used to measure very small distances, usually accurate to 1/1000 of a millimeter, or a solution of this reading is accurate 1 / 1,000 millimeter, or
1 / 1,000,000 meters The micrometer has many advantages over other types of measuring tools such as calipers.
Features of micrometer
Designed for specific micrometry tasks, this instrument covers three micrometer types: an external micrometer for outside dimensions, an internal micrometer for inside dimensions, and a depth micrometer for measuring depths Because of its specialized purpose, it offers limited versatility compared with general-purpose measurement tools, and its measuring range is narrow, typically within 25 mm.
- Micrometer with many sizes: 0 – 25mm, 25 – 50mm, 50 – 75mm, 75 – 100mm,
- The unit of measurement is usually mm or inch
- The most common type of micrometer is Mitutoyo
- There are different levels of accuracy and different resolutions Currently on the market has a resolution of 4 odd numbers (0.0001 mm).
Uses of the micrometer
With its wide measuring range, relatively high accuracy, and ease of use, Panme micrometers are widely used to measure external dimensions, internal dimensions, piston depths, crankshaft dimensions, disc brake components, cylinder bore sizes, and borehole depths.
Micrometer measurements offer high-precision results for very small objects because the micrometer’s spindle and sleeve align along a single straight axis, so rotation translates with minimal error This rigid alignment reduces contact errors that can occur with calipers, where the sliding jaw creates a gap between the face and body and invites dirt and debris to cause misalignment Unlike calipers, micrometers experience less influence from debris in the measurement gap and apply far less force on the object, preserving its true size For small dimensions and high-accuracy applications, micrometers outperform other measuring devices by delivering stable, repeatable readings along the measurement axis.
Therefore, when it is necessary to measure objects with high accuracy, using micrometer will give more accurate results
The structure of the Micrometer
The Micrometer has a fairly simple structure, including the following parts:
Classification of Micrometer
- Threaded shaft with 1mm pitch
- Threaded shaft with 0,5 mm pitch.
Instructions for using the Micrometer
Step 1 : Check Before Taking Measurements
- Check the outer surface: Check if the micrometer is worn or chipped Typically, if the probe is worn or chipped, the measurement results will not be accurate
- Check if the parts with the movement are smooth or not, check if the spin doll has a smooth movement or not
- Clean the measuring surface to avoid dust accumulation
- Check point 0: Before measuring, check point 0 If point 0 is deviated, even with accurate measurement, it will not give accurate measurement results
- For micrometers from 0-25mm, we make direct contact with 2 measuring surfaces Check point 0
- For micrometers from 25-50, etc., we use the corresponding block gauge to check the 0 point
- Check again to see if the dial is really accurate or not
- Loosen the clamp screw, screw the knob so that the measuring head moves according to the size larger than the size of the part to be measured
Apply the probe firmly to the reference surface of the dimension to be measured, then press the knob to move the movable measuring head until it touches the surface of the workpiece to be measured Ensure the probe contact is square to the dimension being measured; if measuring a diameter, the measuring head must be on the face meridian.
- Must keep the center lines of the two measuring torches coincident with the size of the object to be measured
If you must remove the micrometer from the measuring position, first turn the lock nut (brake lever) to release the lock, ensuring the measuring head moves freely before removing the micrometer from the measuring object.
- When measuring against the edge of the moving ruler, we can read the "mm" and half "mm" of the size on the main ruler
- Based on the standard line on the main ruler, we can read the percentage "mm" on the secondary ruler (value for each line is 0.01 mm)
Note: HOW TO ADJUST POINT 0
This 0 point is very important, it determines the accuracy of the measurement If in the case that the 0 point is skewed, we proceed to adjust the 0 point as follows:
In case the point 0 is skewed upwards:
- Definitely spin the doll with the locking pin
- Use the rotary tool to rotate the skewed value
- Check if the 0 points match or not
In case the point 0 is skewed downwards:
- Definitely spin the doll with the locking pin
- Use the rotary tool to rotate the skewed value
- Check if the 0 points match or not
- If point 0 is still skewed, start over
How to read the Micrometer
Gauge size is determined by the position of the spool edge along the ruler: the portion of the ruler to the left of the spool edge forms the integer part The odd part is obtained from the number of lines on the moving tube that align with the reference line on a given tube; multiplying this line count by the ruler’s value (its precision) yields the odd part The measured size is represented by these two values together—the integer part and the odd part.
Method of preserving the micrometer
- Do not measure rough, dirty faces
- Do not measure while the object is rotating
- Do not forcefully press the 2 measuring torches against the measuring object It is necessary to avoid collision, scratching or deforming the anchor
- Limit taking the ruler out of the measuring object and then reading the measured value
At the end of each work shift, wipe the ruler with a clean rag and apply a light lubricant to the locking mechanism (brake lever) to ensure it tightens properly and that the measuring head moves smoothly, then return the micrometer to its correct position in its storage box.