What Is Precision Machining?

Posted on Jul 13, 2021

Precision Machining

1. What Is Precision Machining?

Precision machining is an advanced manufacturing technique used to produce machines, components, and accessories by shaping raw material workpieces at a very high quality. As the name implies the finished component must meet very rigorous finish tolerances and accuracy requirements. It is a machining technology used to produce many large and small components of machines that are used to create objects in our everyday life. As these objects are made up of many small parts, we need precision machining to ensure that these small parts fit together precisely and function as intended.

A lot of different factors have to come together to allow for reliable CNC machining. You need an advanced machine tool, CNC program as well as a knowledgeable operator to get the most of your machining operations. Obviously, advanced processing methods didn’t just appear out of the blue. They are a result of evolution and advancement of technologies, which helped push the limits of machining technology. A defining example would be the incorporation of computer-controlled design that improved performance significantly and consistently, which is also why it is closely associated with the term 'CNC machining'. However, the target tolerances today are much more rigorous.

Bearings
Fig.1 Precision Bearings
 

CNC machining encompasses a wide range of manufacturing operations such as cutting, milling, turning, electrical discharge machining, and others. Conversely, it sees applications in a wide range of different industries such as automotive, medical, aerospace, defense, and so on. Typical precision machining targets include precision locknuts, micro components, and thread grinding. This article provides a detailed introduction to precision machining.

2. Applications and Capabilities

As mentioned above, precision machining is applied in a wide variety of industries. You can use it to create an unimaginably wide range of products, items, and parts for any number of different objects of various sizes. One thing all of these precision machined objects have in common is that they all require tight tolerances variation from part to part, meaning errors in the production of the pieces have to be kept at the very minimum. Required tolerances can go down to a margin of just 0.01mm to 0.05mm - talk about precision! This is why this process features repeatability and a well-controlled production process.

 

precision grinding
Fig.2 Precision Grinding
 

Another application of precision engineering is when you need to repair or restore tools or components. Anyone working in the manufacturing sector will be aware of this, because most machines, tools, and components all require calibration and check-ups to maintain or restore them to their original state after using them for some time. The most frequently used manufacturing equipment is computer-controlled heavy-duty machinery that is meant to remove substrate material to create intricate components and parts. Sometimes, high-speed robotics and photochemical processes may even be used to fulfill the intended result for the final product.

Whether or not a precision components provider has the necessary capabilities depends on the experience and technical knowledge of their engineers and designers, the quality of the machine tools that they use, their high-quality inspection equipment, and their machine operators. OEM and ODM precision machining providers need to have the flexibility to machine components from different materials with specific designs and sometimes material requirements. Therefore, to compete in this area,  manufacturers need to offer a whole turnkey solution including prototype design, testing, processing, customizations, and ideally small-batch and mass production capabilities.

3. How Does The Whole Process Work?

Precision machining is essentially a subtractive process that utilizes custom software, engineered tools, and raw materials such as plastic, metal, and ceramic to create the desired fine-featured products. It is often undergone according to the instruction generated by computer aided design (CAD) and computer-aided manufacturing (CAM) programs. These programs and the generated blueprints make meeting tight tolerances much easier. On a side note, many of these designs start as hand-drawn sketches in the initial phases despite eventually being fed into engineered and computer-aided programs.

To achieve the highest precision, the machining process of a component is split up into several steps. Each one contributes to high-accuracy parts that meet very high tolerances. As mentioned earlier, ultra-precision processing can involve different cutting operations, such as milling, turning, drilling, honing, grinding, and others as well as heat treatment. Usually, we can expect the following stages  in today’s manufacturing world:

  • Customer Request with part drawings, material requirements, specs, etc.
  • Precision Components Supplier (re)designs the part and makes adjustments if necessary
  • Raw material Inspection
  • Prototype Machining & Testing
  •  Primary Machining
  • Optional: Surface and/or Heat Treatment
  • Secondary Machining/Finishing
  • Inspection
  • Shipping of Finished Parts
  • Many leading Precision Machining Providers also implement in-process inspections after each production step to ensure the highest precision and quality.

    4. Machine Tools and Materials 

    Precisicion CNC machining technology can require different types of raw materials, depending on the component and application. Experts in this field usually work with a variety of materials including bronze, glass, graphite, plastics, steel, and other metals. And the types of tools that are used are usually dependent on the size of the production and the materials involved. This is why machinists must be experienced and adept in the machining process inside-out. They need to be able to assess the requirements of the project and determine what kind of materials and tools need to be utilized. As there is such a wide range of applications, the machine tools options are also manifold. The most common machines in today's machine shop are milling machines, turning centers, EDMs, and boring machines.

    SWISS Lathes / Turning Centers

    Swiss lathes, also known as Swiss CNC turning centers, are designed for high-performance metalworking applications especially for manufacturing tiny components, at a high operating speed. Therefore, they are an excellent choice for high-accuracy requirements. The swiss-type lathe was originally invented for producing extremely small and intricate parts in Swiss watches. Today, Swiss lathe machines employ CNC systems to provide a broad category of swiss machining operations across the industries, obtaining more and more popularity in the market. With the equipment, the tolerance within the high-performance turning process can be down to tenths of a thousandth of an inch.

    Milling Machine

    A milling machine is utilized to perform sophisticated milling, which is nothing more than the cut that is made through the rotation of a tool that has several edges known as teeth. These teeth enable movement in any direction as the precision milling machine cuts the workpiece to be formed into the optimum shape. When one talks about a milling machine with maximum operation accuracy, he or she is most likely referring to the precision milling machine. There is also a great possibility that the unit is equipped with a computer numerical control feature that enables the most accurate cut for drilling or other processes involving the removal of chips from even the smallest parts.

    Electrical Discharge Machine

    EDM machines are also very common tools for precision machining. The primary benefit of using EDM machines is that the likelihood of damage to the metal due to fixed electrodes is relatively low thanks to the continual supply of wire. Moreover, since EDM machines can work with hard material, a sub-machine for thermal treatments would not be necessary, thus the surface of the metal shape would be less likely to become distorted due to the absence of heat stress on the metal shape. As a result, smaller and more sophisticated metal shapes can be easily machined with high accuracy.

    Grinder

    A grinder for precision machining employs a grinding wheel as the cutting tool. Utilized for several different grinding and rubbing and coarse mechanical-related procedures, a grinding wheel is an expendable wheel that can be replaced at any time. Grinding wheels can be made from aluminum or solid steel with molecules connected to the surface. The precision grinder is used for materials with relatively small surfaces that require a high degree of flatness and parallelism or a superior surface finish. It is employed for applications requiring tolerances of down to +/- 0.0001" and can accomplish surface finishes of around 10 RMS. It is usually utilized at the final machining processes on a part.

    5. Precision Machining = Operator+Software?

    Supervisors or operators must be very familiar and experienced with different processes, equipment, and CNC software. They may even have to use a combination of mills, lathes, drills, grinders, and even automation equipment such as robotic arms or whole work cells. But running, operating, and overseeing a CNC machine is not just pushing a few buttons, even though modern machine tools do most of the heavy lifting for you. An ideal operator needs to be certified, trained, and educated with good communication skills and problem-solving abilities in case something unexpected happens.

    To summarize, here are some of the most important skills an operator has to possess:

  • The operator needs to have excellent communication skills
  • The operator needs to be able to work with people from a culturally diverse background A precision machinist should have excellent problem-solving and analytical skills to ensure that the projects can always yield successful results.
  • Additionally, precision machinists should stay competent in the following aspects of the machining process:CAD and CAM software, Technical drawings, Computer-aided production, Product specification, Materials science and metalworking theories
  • What is true for the single individual is true for the whole SOP of the precision machining process. A professional OEM or ODM parts manufacturer needs to accompany the customer from the first consultation to the final quality assurance and beyond with after-sales services. Precision machining technology is about much more than manufacturing a lock nut or a chuck according to someone’s drawings and specifications. It involves planning, designing, customizing, and budgeting while integrating the necessary inspections and QA and QC procedures to ensure the final product meets the client’s expectations. Read our study case below (7. Study Case) to explore a real-life example.

    machining inspection
    Fig.3 Precision Component Inspection
     

    The final factor we want to mention is the CNC software. To meet the crazy (micron-level) tolerance requirements in today’s manufacturing world, almost all professional suppliers of precision parts make use of CNC software such as CAD and CAM. This software provides the designers, engineers, and operators with tools to plan out the machining operation. The skills and experience with this type of software and the ability to adapt to new technology are crucial to keeping up with the latest standards in the realm of precision machining.

    6. Advantages

    Reliability

    Precision machiningi is carried out continuously without any breakdown no matter the time or day of the week. The raw materials are converted into the final product and ultimately released into the market as high-quality tools. One of the key upsides is that breakdowns are not likely to occur when maintenance is required or during a repair.

    Reduced human labor requirements

    Due to the significant advancement in engineering technology over the years the manufacturing industries have become more and more automated. The process is mainly controlled by robots or computers which minimal human labor to monitor them. This also hugely cut down production costs, as well as the need for supervision and oversight of the process.

    Increased Productivity

    Despite the intricate nature of the operation, it can substantially boost productivity by tending to a massive amount of work such as drilling, finishing, milling, spinning, etc. in a relatively short period.

    Consistent results

    Despite the high production rate, the finished products are identical and have very little chance of errors. The resulted products, in turn, become more marketable due to their consistency, improved quality, and low failure rate.

    Increased profit and reduced effort

    A key benefit is that minimal effort is needed to yield optimal profits. The fact of the matter is that with a metal that undergoes precision machining, not only do you save production cost, but it will also save much of your time and effort which ultimately guarantees highly cost-efficient production.

    Increased accuracy

    Most of the objects and parts undergoing precision machining are used in the manufacturing industries. This includes places where manual turning and milling are required. It can also be utilized in the healthcare sector where accuracies are highly looked upon. In light of this, they are equipped with the ability to operate on a highly accurate basis, thereby completing the intended tasks effortlessly.

     

    7. Study Case: Precision Parts by YINSH

    yinsh precision
    Fig.4 Yinsh - Precision Machining Services (Copyright Yinsh, All Rights Reserved)
     

    Smart Manufacturing

    There are many precision parts suppliers and OEM/ ODM companies that are rooted in Taiwan and export their excellent services to the world market. For instance, YINSH Company located in the central metalworking supply chain is one of the most renowned suppliers for precision machining products, such as precision locknuts, precision parts, thread grinding, and track scrapers. According to Vice President, Jack Wu, the company has exported to over 40 countries so far, including Japan, Korea, Germany, Italy, India, and the US. Based on the automation solution YINSH offers its customers, their smart manufacturing system can track customers’ orders and take care of every detail as much as they can.

    Manufacturing Condition and QC

    YINSH adopts strict standards on all manufacturing procedures to ensure high-precision and quality at all stages. The R&D team, measuring step, and the manufacturing processes are all digitally monitored with their smart manufacturing integration system to make the optimum quality for the customer. All of their manufacturing plants also are in strict compliance with regulations and are inspected regularly for the well-being of the staff.

    Material Selection 

    During the interview, one of the senior sales staff remarked that materials are crucial especially for customers in the EU in a particular context of precision machining. YINSH can assist customers with material selection and proceed to the drawing step for even more flexibility. The drawing step is an important stage for evaluating the geometric accuracy and dimensional accuracy of the drawings provided by the customers. Following compulsory processes like material analysis, heat treatment, and so on, YINSH validates the drawing with the customers to see if all the demands are met.

    Cutting-edge Labs 

    There are many important labs inside the YINSH plants. One of them is the metrology lab, which contains CMM for the final quality control. YINSH has six advanced inspection devices in the lab, and the brands are all famous and reliable ones such as ZEISS and MITUTOYO. You can see one step in the inspection process for locknuts in the short clip below.


    A roundness tester and contour measuring system are included in the precision metrology lab, which is certified by the TAF, and many important issues such as temperature, humidity, and other critical conditions are controlled well in the lab. This ensures that all precision components produced to meet the standard with things every detail and dimension are taken into account. YINSH wants to make sure they are on the same page with their customers.

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