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Tumbling, also known as vibratory finishing, is frequently used in the post-processing of CNC machined parts to remove sharp edges and burrs. However, the narrow groove edges might have been deformed due to the impact from tumbling, causing the groove width to shrink and making it impossible to assemble the C-clip.   The image above shows the deformation at the edge highlighted by the red arrow.   To address this issue, the following improvement plan has been proposed: ・Increase the Chamfer Size Design a larger chamfer on the edges to accommodate for any potential deformation during the finishing process, ensuring the slot remains adequately sized for the C-clip. ・Cease Tumbling Originally, tumbling was used to deburr and break the sharp edges. If vibratory finishing is ceased to prevent the unwanted deformation, the part must be machined with a chamfer on the lathe to deburr. ・Increase Tolerance Adjust the groove dimensions to include a wider tolerance on the upper limit, or suggest to the customer to slightly increase the groove width to ensure assembly with the C-clip.   By implementing the above changes, we aim to prevent similar issues in the future, ensuring parts are machined to specification and can be assembled as intended.   ...

The QC team inspected the motor plate, which was machined by the CNC milling machine center (see the photo below), and found a misalignment at the bottom of a bore.     Our engineering and QC team have preliminarily determined several possible causes for this issue:   1.) Tool Path Error Root cause: The CNC programming code might have an error in the tool path, could be due to incorrect coordinates, tool offset settings, or a miscalculation in the G-code.  Corrective action: To review the G-code is a must.   2.) Tooling Wear or Breakage Root cause: The misaligned bore might be caused by worn out or broken cutting tools during the production.  Corrective action: The operation team should ensure the cutting tool is in good condition regularly.   3.) Machine Calibration Root cause: CNC machine centers need to be properly calibrated regularly. Issues with the machine's axes alignment or spindle speed could cause such discrepancies. Corrective action: To verify all axes are correctly aligned and the spindle is functioning properly.   4.) Material Issues Root cause: The material might have moved or deformed unexpectedly during CNC machining, possibly due to improper clamping or residual stresses in the material. Corrective action: Ensure the workpiece is clamped securely without any movement possibility. Also, look for any signs of deformation or stress in the material, annealing the material to relieve internal stresses.   5.) Human Error Root cause: Incorrect setup by the operator, like wrong tool selection, improper cutting tool length offset, or setup of the workpiece. Corrective action: Operator training to make sure the operator is well-trained and follows all procedures correctly.   This kind of defect is critical in CNC precision machining, as it can affect the functionality of the part assembly. This approach ensures that issues like bore misalignment or other machining errors are identified promptly. By implementing immediate quality improvements, we can prevent similar problems from occurring in the future, maintaining high standards of product quality and customer satisfaction. ...

Since the late nineteenth and early twentieth century, globalization has gradually led to international trade, capital and investment flows, migration, and the knowledge dissemination. From the Q&A below, let’s take a look at how Taiwan as a west Pacific island country reaches such outstanding achievements in the CNC machining industry, which blooms and stands out from the intense competitions of globalization.     - The origin of CNC machining service in Taiwan     1950-1980 is a period called “Taiwan Economic Miracle”, when Taiwan benefited from the late-development advantage of industrialization. The industrial globalization after WWII enabled multinational corporations to look for lower-cost manufacturing bases worldwide. Therefore, with low labor rates and production lines, economics in Taiwan began to prosper, led by the manufacturing industry that processed and exported.       Export-oriented Economic Growth       - The strength of CNC machining service in Taiwan   The Industry of CNC machining service is quite dense in Taiwan. It features convenient transportation, vertical integration of services from raw materials, fine machining to surface treatment and so on, and horizontal integration of services, providing casting, forging, rolling, extruding, cutting, high energy beam machining, chemical etching, etc. Therefore, the industry of CNC machining service Taiwan is more capable of product structure breakdown and integration, allowing highly flexible manufacturing efficiency.     - The future of CNC machining services   Due to the breakthrough of Internet of Things (IoT) concepts and techniques, automatic control and wisdom management will play an important role in the industry of manufacturing: 1.) Multi-axis CNC machines with high performance and precision with data analysis, automatic corrective feedback to increase the efficiency of high precision machining.   2.) CAD softwares to complete component modeling and machining procedures to shorten the time from design to finished product, and to also increase the flexibility of production lines.     3.) CNC machines with sensors to measure online, collect production data, optimize plant activation, and overall capacity.   ...

    Stainless steel could last longer with passivation treatment.       One of the most frequently asked questions from our customers is that why stainless steel needs passivation(*Ref) treatment when it already has good anti-rust quality. It seems that workpieces after passivation treatment only look more polished and completely degreased on the surface. Actually, if we only degrease and dry the workpieces without passivation, there is no obvious difference visually. Therefore, here APPORO would like to thoroughly discuss and introduce passivation treatment from the perspective of professionals.     What is passivation treatment?   Passivation treatment refers to a chemical post-treatment in order to enhance the inherent anti-corrosion quality of stainless steel, which is different from the traditional metal pickling that removes oxide layers on the surface, and from the chemical film treatment before coating. After passivation treatment, there will be a protective oxide film on the surface of the stainless steel workpiece. This invisible film is extremely thin. Its thickness is smaller than 0.0000001 inch, around 1/100,000 the thickness of human hair. Generally speaking, workpieces after passivation treatment are clean, bright and rust-proof on the surface.   Basically, this oxide film forms naturally when the workpieces get exposed to the oxygen in the air after manufacturing, polishing, or acid cleansing process. Under ideal conditions, the surface of the workpiece will be totally covered with the oxide film. But it will also be covered with iron particles from cutting tools or the rust on them, or the ferrous particles during manufacturing. Although these manufactured stainless steel items are seemingly smooth and clean on the surface, under certain conditions these invisible and scattered particles could possibly lead to the corrosion and do damage to the quality of the protective oxide film on the surface that previously formed. Sometimes rusty spots could even be identified.   Besides, as to smoothly remove the iron chippings from the cutting tools, AISI 303, so-called free cutting stainless steel, sulfides are added. However, the sulfides on the surface also could result in rust and rusty spots after the exposure to certain environment.     When do we need passivation treatment?   Overall, there are several inevitable factors during manufacturing that could sometime cause rust and rusty spots on the surface. If the application requirement of the workpiece is rather strict, such as environment with high salinity, strong acid/base, corrosive chemicals, high temperature, or high humidity, passivation treatment is recommended. Or the material could be replaced with medical grade stainless steel AISI 316L. This grade of stainless steel is often used in some of the harshest environments such as medical industry, food, energy, construction and agricultural industries.   *Ref: Learn more about Passivation ...

  Perpetual motion machine remains a dream unattainable.       As a manufacturer, APPORO has quite an understanding of design of machine tools and the way they work. We figure how to optimize our CNC manufacturing procedures and to enhance the efficiency all the time, so as to reduce the manufacturing costs. Hence, when knowing there is so-called machine design which could conserve energy or enhance efficiency, APPORO surely looks into its operating principle in details and evaluates if it matches its advertised performance. Not surprisingly, the actual test result often falls short. Speaking of that, several well-known scams in history also adopted this kind of conceptual design, claiming to have created perpetual motion machine(*Ref) to defraud.     What is a Perpetual Motion Machine?   Perpetual motion machine refers to a machine that does motions constantly and works without energy input. There are two major categories in terms of perpetual motion machine. The first kind violates the first law of thermodynamics as it does work without energy sources. The first law of thermodynamics states conservation of energy, indicating the total energy stays constant in an isolated system, and that no extra energy emerges in that system. Any machine that claims to produce energy from nowhere falls into this category.   While the first kind of perpetual motion machine was proved to be impossible, discussions about the second kind of perpetual motion machine were put on table right away. Its design makes use of the energy outside of the isolated system such as heat and wind energy, striking the balance so that the system could operate perpetually. However, energy would eventually be exhausted from the working machines. The just balance could only be reached if there is energy input, so it still failed to forever motion without additional energy.     After Perpetual Motion Machine   The idea of perpetual motion machine has existed for centuries. Based on the scientific understanding nowadays, it remains a dream unattainable. However, there are still a lot of “scientists” engaged in the invention of perpetual motion machine, one after another. Basically these “scientists” are:   1.) Rookies: They barely know a thing about the concept of perpetual motion machine. They often mistake certain device for perpetual machine, which, in fact are device that absorb energy in the dark. For example, human body.   2.) Genuine scientists: They hold the firm belief that science has to be challenged all the time, thinking that thermodynamics could also be wrong or should be revised, as Newton’s law of motion was revised by theory of relativity quantum mechanics. It is never easy to overthrow a law, but their attitudes are admirable. These people are the most likely to invent perpetual motion machine.   3.) Fraud: Even in this era of information explosion, we can still see those who claim to have invented perpetual motion machine. They use sophisticated physics terms and fancy words to convince other to take their scientific results and defraud them of investment. But, until now, all perpetual motion machines are proved to be fraudulent.     Will The Dream Come True?   Perpetual motion machine has always been the dream in the field of science. Just like alchemy for development of chemicals, as many efforts are put into this probably impossible techniques, many relevant techniques are then created. As a pragmatic CNC manufacturer, although we might not believe the concept perpetual motion machine would be ever realized, we could not deny the fact that the progress of science and mechanic design derives from the constant efforts of researchers. Holding the same attitude, APPORO will non-stop updates and introduces new techniques and shares more case studies, hoping to have in depth academic exchange and to contribute to the manufacturing field.     *Ref: Learn more about Perpetual motion. ...

It is inevitable to have burrs on the cutting or hole-drilling edge during the milling while milling parts. The size of burr is usually relevant to tool wear condition, feeding and rotary speed, material properties, cutting fluid, etc. The left burrs on the workpiece not only could get operatives scrapped, but also could lead the dimensions exceeding the tolerance. Therefore, CNC manufacturers all regard burrs as a huge enemy against workpiece quality. Previously, APPORO shared a case study on deburring the die casting parts. In that case, burrs formed on account of reamer wearing, and after APPORO promptly renewed the reamers, conducted a full inspection, and removed the burrs, we coped with the quality crisis.   Most burrs on the end/edge of the parts could be removed on the CNC machine through chamfering(*Ref). However, some have to be manually removed as the burrs are where the machine can hardly perform, resulting in the high overall manufacturing cost. If you ever encounter the above situation, take a look at two concrete cases below. See how APPORO make excellent use of decades of experience in CNC manufacturing to overcome all kinds of challenges.     Across Milling Burrs   Basically, milling is about cutting round bar materials into required ID/OD dimensions with high-speed rotary tools. If we are to mill flat surface onto the cylindrical side of round bar materials, the CNC milling machine should be installed with driven tool holders, where face milling cutters are mounted. When it comes to the step of face milling on the side, the round bar stops spinning and aligns the face milling cutter with the part to be machined. Then, the milling cutter starts spinning in right/down or left/right direction to side mill the workpieces, until the depth and width across flats are as required.     We use two cutters to precisely and quickly face mill the rod, but highly possible to cause burrs at the end of the flat surface.       From the poppet stem photo above, the head of this OD 8.0 mm workpiece features 7.0 mm width across flats. In other words, the surface has to be 0.5 mm in-depth on one side. First, APPORO used two cutters with 7.0 mm space in-between to face mill the 8.0 mm OD with symmetry from the end of the workpiece, in the same direction with the axis. The processing was precise and quick, but highly possible to cause burrs at the end of the flat surface, which was also around the edge of finish part of the workpiece. As there were not sufficient tool holders in that CNC lathe machine, it was impossible to remove the burrs on the machine. In that way, APPORO could only manually remove the burrs with a pneumatic deburring tool. However, the inconsistent force exertion led to the uneven chamfers and the disqualification.     The inconsistent force exertion led to the uneven chamfers marked by red arrows. The undercut marked by red circle is very rough due to the fact that the cutting tool is worn out.       When APPORO reviewed all the milling process, we decided to substitute a better CNC lathe machine with more functions, installing face milling tools in its driven tool holders on the side. So, we can machine the 7.0 mm across flats directly. When the 0.5 mm deep surface is completed on one side, the C axis of the lathe machine rotates by 180 degrees and machines 0.5 mm deep surface with an end mill. In the following, APPORO uses the chamfering tool to remove the burrs from the four edges. After this adjustment, APPORO stays away from the risk of inconsistent force exertion of manual deburring and enhances the production efficiency.     To mill the across flats and remove the burrs directly on a powerful CNC lathe machine.       Burrs from Hole Drilling on Slopes   Generally, after hole drilling, noticeable burrs formed around the edge of the exit surface. If there is still enough space around the hole, chamfering to deburr is still available. However, if the exit surface is not perpendicular to the hole, meaning that the exit surface is a slope or curve, chamfering is not an option to deburr. Here are some alternative plans we can adopt:   1.) Blast Using the momentum of the high-pressure gas to strike the surface of the workpiece. Available to polish the surface and deburr with evenness and efficiency. However, after blasting the surface could turn slightly matte.   2.) Tumble The tumble theory applied to have tooling rub against the workpiece with high frequency. Available to polish the surface and deburr with evenness and efficiency. Unavailable for overlong/overweight workpiece or workpiece with external thread.   3.) The universal deburring tool A unique chamfer tool with its cutter and spring attached. It allows removing the burrs around the edge on both ends at a time. Unavailable for hole under 3mm ID.   Can’t figure out how to deal with the nightmare of burrs? It is time to contact APPORO now. APPORO is going to help you overcome all the problems in manufacturing, based on our experience for decades in this field!   *Ref: Learn more about Chamfering.  ...

The trade war between China and the US has been constantly escalated, which draws opposite sides of opinions from experts in all fields. On one side, many think tariffs limit the benefits of free trade, raising the cost of living, and failing to bring positive effects on the manufacturing in the US. On the contrary, the others believe the trade war is beneficial for the US economy, as it brings back more job opportunities of manufacturing to the US. No matter what the future will be like, we have to put the emphasis on currently the two most impactful tariffs: a 25 percent tax on steel and 10 percent tax on aluminum. The impacts of them could be everywhere, starting from Coke, vehicles to industrial equipment and other high-end manufacturing.     Tariff Avoidance Strategies   In the aspect of the manufacturing industry in Taiwan, the trade war leads to the rise of all kinds of costs. For example, materials, manufacturing, and sales are all influenced, directly or indirectly. Here are the strategies most corporations adopt:   1.) Reduce the cost of supply chain   2.)Switch to another supplier with lower cost   3.) Revise design and change manufacturing way to cut down manufacturing cost, and lead in industry 4.0 with automation (and unmanned factory)   4.) Stand still and stick to the current operating strategy, while bearing the enormous pressure of continuing raising costs during the trade war.     As the trade war continues, although it does not force corporations to shift back their massive production to the US, due to the fact that the labor cost in the US is still higher than it in China or countries oversea. Gradually, it apparently accelerates the speed of which corporations move out their production from China. Since 2019, many CNC manufacturers in Taiwan have indeed received orders from China, most of which are from the purchasing offices in China. These purchasing offices are assigned by their parent companies in the US tor purchase from Taiwan or Southeast Asian countries. Although in the first half of year the accumulated exports of Taiwan slightly dropped, however, in certain industries such as IT industry the accumulated exports are constantly growing.         Taiwan's exports highly rely on China market but also influenced by tariffs.   (Ref: https://cus93.trade.gov.tw/)     In the trading storm between these two great and conflicting countries, CNC manufacturers in Taiwan might benefit from the transferred order temporarily, in the meantime, we should also figure out how to prevent ourselves from being dragged into the storm next time.  ...

Unified National is a standard commonly used by the United States and Canada in for Inch Screw Threads where the flanks of the V have an angle of 60° to each other. At first, UN(*Ref) only included four basic categories: UNC, UNF, UNEF, UNS, and then UNJ and UNR were gradually added to the standard. Originally developed to meet aerospace requirements for a screw thread, to provide maximum fatigue strength for fastening safety critical components subjected to high stress loads, is the UNJ threading profile. Nowadays, it is also widely used in high-end automotive and robotic automation.     UN Thread Classes   According to UN standard, there are three different classes (1A, 2A, and 3A) when it comes to external threads, and for internal threads there are three as well (1B, 2B, and 3B).   1A and 1B: Refers to the thread fitting with the most loose tolerance, where there is a huge allowance. This class of thread fit is applicable to easy assembly and disassembly.   2A and 2B: The major class in the industrial and commercial applications, such as machine screws and fasteners. This class of thread fit is interchangeable and stable in regard to quality and assembly.   3A and 3B: Applied to commercial products with high quality, this class of thread fit requires compact assembly with an extremely small allowance. Therefore, 3A/3B thread fitting is usually seen in crucial design with safety requirement in commercial or aerospace industry products.     The UNJF-3A adjustable thread gauge is with an extremely small allowance.     As for external threads, the tolerance of 1A class thread fitting is larger than it of 2A class fitting by 50%, and by 75% than it of 3A class fitting. Samely, for internal threads, the tolerance of 1B class fitting is larger than it of 2B class fitting by 50%, and by 75% than it of 3B class fitting. Taking the 5/16”-18 UNJ-3B thread as an example to show how to read UN thread specification, the 5/16” stands for the major diameter, the 18 UNJ suggests that there are 18 threads per inch in the UNJ threads, and the 3B refers to the finest class of the UNJ internal threads.     Trivia about lathe UNJ threading   In the following, APPORO is going to introduce UNJ threads. Initially released December 1965, the military specification MIL-S-8879 is mainly applied to aerospace fasteners. There are internal thread and external thread specifications when it comes to UNJ threads, which based on the pitch can be categorized into UNJC, UNJF, UNJEF, and UNJS. UNJ threads are different from UN threads in the respects below:   1.) external threads: The roots of regular UN threads will be V shape bottoming, while the roots of UNJ thread are strictly specified to be semicircular bottoming. This kind of circular roots can slow down the wear rate of sharp cuts during processing and increase the fatigue strength of threads.     2.) internal threads: In order to assemble with the semicircular bottoming of external thread, the minor diameter of an UNJ internal thread will be slightly larger than it of a regular UN internal thread. As internal threads are rather unlikely to break from the internal stress, there is no specifications for the major diameter roots of UNJ internal threads to be semicircular bottoming.     3.) The symbol for all UN external threads is “A”, while for all UN internal threads is “B”. In addition, for J series threads usually the required thread class is 3A/3B, which is the highest fit, and the second most common thread class for J series threads is 2A/2B. On the other hand, for UN threads the thread class is commonly 2A/2B.         In the process of lathing UNJ external threads, sharp cuts should be equipped according to the specified root radius (between 0.15011 pitch and 0.18042 pitch), so that the roots of the external threads could be smooth semicircles in a row in shape. As the roots of an external UNJ thread are special semicircles in shape, its minor diameter is slightly larger than it of a regular external UN thread, and that is why it could not match other Inch Screw Threads of the same specifications. For example, if we drive an ⅜”-16 UNC nut with an ⅜”-16 UNJ screw, the minor diameters of these two would interfere with each other, resulting in the assembly failure. However, using a larger tapper to manufacture the internal thread of the ⅜”-16 UNC nut could prevent the minor diameters from interfering and avoid other assembly problems.     On the contrary, if we would like to drive an internal UNJ thread with a regular external UN thread, since there is no specifications about the major roots of an internal UNJ thread being semicircles in shape, basically an internal UNJ thread could match an external UN thread of same specifications. The difference between an internal UNJ thread and an external UN thread is that the minor diameter of an internal UNJ thread, as known as the size of its tap-drill hole, is larger; therefore, the minor diameter of the internal UNJ threads could match the semicircular shape external roots of the external UNJ threads. For instance, under some special circumstances, there will not be any problems driving an ⅜”-16 UNJ nut with an ⅜”-16 UNC screw.     In comparison with hundreds of thousands of thread specifications and applications, thread manufacturing and inspection are rather simple. However, their importance is often underestimated, leading to assembly failure and possibly affecting the overall product equality. Find yourselves a CNC expert with thread manufacturing proficiency and experience like APPORO so that the quality of your products are guaranteed!       *Ref: Learn more about Unified Thread Standard  ...

    To use NO GO of the standard thread gauge for the inspection criterion for threads before plating. After plating, the threads have to pass the standard thread gauge inspections.       How to Control the Thread Size Before Plating?   As it is mentioned previously, the goal of OD control can be easily reached under stable CNC processing. Generally, after CNC processing, the threads of a non-plated component have to pass the thread gauge inspection so as to pass the QC inspection. Nevertheless, for components that need to undergo plating process, the manufacturing and inspection procedures will be different from the former. According to the requirement of our Swiss dental equipment supplier client, APPORO has to be discreet than ever for inspections. See the examples below:   Based on the required plating film thickness, APPORO has to leave some room for it during CNC processing, and use the pre-plated thread gauges for inspections. See the photo below. If the required plating film thickness is 1-3um, the major, pitch, and minor diameters should all be +0.02/-0mm larger than the standard dimensions when manufacturing the internal thread M13.2x0.3-6H. Then, the threads need to pass the inspections of the enlarged customized M13.2x0.3-6H +0.02/-0mm plug gauge before plating. After plating, the internal threads need to pass the inspections of a standard M13.2x0.3-6H plug gauge. Once they pass the inspection, they can be approved for shipment. If there is an external thread on the plated component, after CNC processing, the pre-plated ring gauge inspection will be necessary. And then, the inspection of a standard ring gauge should then be conducted.     What we can do without pre-plated gauges?   However, the customized pre-plated plug/ring gauges are all expensive, which are only needed for components that demand extremely high precision, but not for all components. With the long time CNC manufacturing experience, APPORO suggests to use NO GO of the standard thread gauge for the inspection criterion for threads before plating. That is, the threads could perfectly screw in the NO GO of the standard thread gauge without loosing. After plating, the threads have to pass the standard thread gauge inspections, a.k.a. GO and NO GO inspections.     This inspection is more available for components with plating film under 5um thickness. For components with plating film over 5um thickness, as its plating is for anti-corrosion purpose, and the precision requirement of it is usually lower. Even the ready made standard screws and nuts can be the inspection tools. Or, before plating the threads should be able to screw in the NO GO of the standard thread gauge but slightly loose. And then, the threads should pass the GO and NO GO inspections after plating.     Plating and thread making are common techniques when speaking of CNC manufacturing components. Before and after different procedures, the concern will also be different. APPORO has devoted long time and and much efforts to CNC machining services, systematically learning from the processing experience in this field and turning it into application to increase the manufacturing efficiency and yield rates. Should you have any technical questions relevant to controlling size before/after plating, do not hesitate to contact us.     Learn more about thread gauge measurement:   Thread Gauge for instant measurement ...

There are numerous items in our daily lives that need threads for assembly and secure. In the applications of some precision industries, the precision of thread is highly relevant to the smoothness of component assembly, so rigorous manufacturing and inspection are necessary. Regarding manufacturing threads, previously we publish an article about it in details, where you can select your best ways for manufacturing depending on materials, amount, and precision. We will also talk about how to manufacture pre-plated thread later in this article.     How to inspect the threads?   As you can choose the most appropriate ways to manufacture threads depending on the needs, you can also customize the thread inspection based on the precision, functionality, and so on. Generally speaking, if tolerance and the intensity of threads are not really the concern, ready made bolts and nuts are available for shop-floor inspections. When the nuts/bolts successfully run onto/into their counterparts, they pass the shop-floor inspections. But if tolerance and the intensity of threads are the concern, advanced inspection methods such as thread gauges, 3-wire method, micrometer, vernier caliper, projector and coordinate measuring machines, can be used to measure the threads accurately. Regarding the basic introduction about thread inspections, you can take a look at the previous case study from Apporo.   In the extremely rigorous precision industry, the design thinking ranging from purpose, materials, manufacturing, post-manufacturing, to even packaging are taken seriously, so as to ensure the quality of products during mass production and the various functionality. Take the design thinking of one of Apporo’s clients, the Swiss dental equipment supplier for example. The handheld dental equipment have to be comfortable for long-term use, able to prevent from occupational injury, and conforming with hand ergonomics. Therefore, details like size and the design of center of weight are highly valued.     What should we learn about pre-plated part?   One of our CNC machining services is mainly in charge of the supply of medical grade stainless and brass components manufactured on CNC lathe. Besides, if there is cosmetic or anti-corrosion purpose for brass components, nickel or chrome plating will be added as surface treatment. In general, the film thickness of plating and its anti-corrosion ability are positively correlated. However, when it comes to the dental equipment, the anti-corrosion ability is not the a priority concern. Instead, what really matters is that the dimensions of the components are still within the tolerance after plating, to make sure the components are in a good assembly condition and function.   For instance, after 1-3um nickel plating, the outside diameter a cylinder brass component and its tolerance should be 9.50 +/-0.02mm. In practice, we manufacture the OD 10.0mm round rod materials into OD 9.48-9.50mm. With nickel plating which requires 1-3um thickness, the OD of the plated products could be within 9.50 +/-0.02mm.       Detailed instruction of pre-plated OD manufacturing is usually shown on the professional CAD drawing.       Learn more: How to Manufacture Pre-Plated Thread (Part 1)   ...

The definition of a thread is a spiral surrounded ridge structure with surrounding spirals in the round hole or outside of the cylinder. In terms of external threads, the peak of a thread ridge constitutes the major diameter, while the base of a thread ridge the minor. For internal threads, it is opposite. Besides, between major diameter and minor diameter, there is a pitch diameter, as known as an effective diameter whether it is an external thread or an internal thread. The purpose of the pitch diameter is to see if the thread could assemble with its matching thread successfully. If so, the distance between thread flanks will be equal. Because a pitch diameter is crucial to the assembly of the threaded parts, we generally use Three Wire Method or thread gauges for checkups.      Here, let’s discuss the common methods of producing internal and external threads respectively during CNC manufacturing process:   Internal Thread   1.) Thread tapping   Usually refers to taper/second/bottoming three steps thread tapping. It uses a thread tap to cut the inner hole into an internal spiral surrounding the ridge. During the manufacturing process, cutting fluid has to be constantly filled in to lower down the temperature and to help residue removal. Applicable when the material is hard or brittle.   2.) Fluteless tapping   Compared with thread tapping which uses cutting to remove residue to process with the internal spiral, this method adopts thread tapping and then squeezes to form the internal spirals after drilling the pilot hole. Check out our previous case study for your reference. Applicable to the thread tapping of aluminum or brass made parts of which the threads are with better strength and stability.   3.) Internal threading tool   Identical to thread tapping that internal threading tool is also a method using cutting to process the thread. Internal threading tool has its advantage that it is able to maximize the effective thread hole depth of the blind hole. The limitation of the internal thread tool is that it is unable to process the threaded hole with too small inside diameter. Usually, it is recommended to use thread tapping for threads smaller than M5.       Due to the incomplete residue removal of thread tapping process, the tapping breaks in M2 blind hole of the aluminum alloy component. Using fluteless tapping could be an alternative here.       External thread   1.) Thread rolling   Using cold forging to shape the external threads, this method is applicable to ductile materials. Before forming, the outside diameter of the component needs to be processed into the pitch of the thread. After forming, thread will be complete, precise, cosmetic with high intensity. This forming theory also applies to outside diameter knurling. Take a look at APPORO’s previous case study.   2.) External threading tool   Using cutting to remove the residue to process the external spiral. Cutting fluid needs to be added to help lower down the temperature and remove residue. Applicable to ductile and brittle materials.   3.) External thread tapping die   A disc-shaped external thread cutting tool. To use the external thread tapping die, the outside diameter of the round bar material needs to be slightly smaller than the major diameter of the external thread tapping die. Also, chamfer at the end of the round bar material will help the process of the external threading die. Using external thread tapping die to produce threads is more efficient, precise, while the tapping die costs more and is more applicable to threads with smaller outside diameter and components shaped like bearing shafts.       The low carbon steel component is a piece of demonstrative equipment for tensile force test. Concerning that only with high intensity can threads pass the destructive test, thread rolling is adopted for forming process.   ...

Stamping is a manufacturing method which shapes sheet materials rapidly through procedures like shearing, blanking and bending. Stamping features the precise, mass, economic and effective production that it can produce fast and repetitively. We will talk about the difference between regular stamping die and fine blanking press later. Before, APPORO also shared a case study on progressive stamping die here: https://www.apporo-cnc.com/news_detail.php?menu_s=400&sn=52&page=0   The cut edge of a finished product of regular stamping die is usually rough and deformed with obvious cracks, and of parts with more thickness, this condition becomes more apparent. This happens because when regular stamping dies function, they push the punches to bend and cut the materials, and then remove the finished cut part or waste materials from the sheet materials. If there is a need for precise assembly on the cut edge, a secondary processing work will then be inevitable to fix the cut edge. Otherwise, if there is no need for the precise assembly or cosmetic purpose on the cut edge, regular stamping dies will be a utility option for mass production.     How to reduce the cost of production? Instead of using poor-quality materials, look for advanced production techniques!       For example, the picture below is a counterweight part of a measuring device. As the counterweight part is not for cosmetic purpose and its cut edge is not for assembly, it is appropriate to use regular stamping dies to mass produce.     The counterweight part is made of SPHC materials with 10mm thickness. Manufactured with regular stamping dies, the cut edge of the part is rough with the bend and deformation.       Fine Blanking Press    Fine blanking press provides parts with the smooth and vertical cut edge with precise dimension tolerance. Compared with regular stamping dies, the design of dies of fine blanking press has many differences. Take the blanking dies for fine blanking press as an example. There will be V-shaped convex rings designed around the upper stamping plate near the fringe of the cut edge. While blanking, the upper and lower plates will clamp the parts. After that, the blanking punches will fall to cut the sheet materials. Meanwhile, there will be ejectors same size of the blanking punches with counter-pressure below to withstand the sheet materials upward, ensuring that the cut edge of the sheet materials will not bend and deform after cut. Generally speaking, the width of the cracks between the blanking punches of fine blanking press and the upper/lower plates will roughly be 0.5% as much thickness of the sheet materials. That is almost 1/10 as much width of the cracks of traditional stamping dies, so as to prevent the cut edge from tearing.     The pole piece is made of SPHC materials with 6mm thickness. Manufactured with fine blanking press, the cut edge of the part are smooth and vertical, which is not second to the quality manufactured with milling or laser cutting.       With the numerous features above, fine blanking press dies are quite suitable for manufacturing 2-dimensional parts. Also, when it comes to mass production, fine blanking press has an advantage in its low cost compared to CNC milling and laser cutting. As what is stated above, if we use CNC milling for 2-dimensional parts with precise assembly and cosmetic purposes, the parts will have high precision but with high manufacturing cost and low efficiency. If we use laser cutting, although the manufacturing cost is low and the efficiency is high, the dimension precision is lower, only +/-0.2mm tolerances. Besides, it is easy to have burned marks, sharp edges, and burrs on the cut edge when we use laser cutting, so we will need secondary processing to reach enough precision and cosmetic requirements, and the manufacturing costs and procedures will then increase. If you plan to cut down the manufacturing cost, increase the manufacturing efficiency, and have the needs of precise assembly and cosmetic appearance, take fine blanking press into consideration for your projects.   Learn more about stamping: Progressive Stamping Mold: Spacing Limitation ...