Process And Precautions For Professional Non-standard Parts Processing

Process and precautions for professional non-standard parts processing

The most serious hidden danger in the processing of non-standard parts is not caused by the insufficient number of relevant production equipment, but because the entire production management process is not running smoothly, thus all the professional and technical strength accumulated over a long period of time is wasted.

Nowadays, many manufacturing plants invest more than one million yuan every year to purchase new processing equipment. However, the probability of rework when producing the same type of parts is still fixed at a level of 15% and cannot be reduced. The most fundamental reason for this phenomenon is that the specific machining execution links have not been implemented in place.

Design communication sets direction

Customers cannot clearly explain their needs, which is the first difficulty in non-standard processing. In 2025, there was a company in Suzhou engaged in the manufacturing of automobile and motorcycle parts. Its drawings were revised three times. The main reason was that the engineers did not ask clearly the details of the expansion and contraction of the parts in an environment of minus 30 degrees. This approach directly led to large-scale batch scrapping.

During the communication process, it is necessary to ask clearly and thoroughly about the functional status, working condition status and tolerance details in one communication. It is best to allow customers to bring old parts or samples to the site. The more specific and detailed information the designer obtains, the lower the cost of later modifications and version iterations. At the same time, the establishment and accumulation of technical files can become faster.

Process planning and equipment selection

If the same part is processed by milling or turning, the time required for its production will be very different, and this difference can even be as much as double.

In Changzhou, there is a factory that specializes in the production of precision parts. In 2024, they adjusted the manufacturing process of a batch of hydraulic valve cores, changing the original five-axis milling method to a combination of turning and grinding. After this process improvement, the production time of a single part was reduced from more than 40 minutes per hour, or 42 minutes, to only 19 minutes.

When you are planning, you must first split the various processes, remove excess material during rough machining, ensure accurate dimensions during finishing, and determine the final performance through heat treatment. The order of these steps cannot be messed up at all. If you encounter more complex parts, you must also reserve some space or time in advance to cope with the needs of EDM or laser cutting. Don't be busy until you suddenly realize that the existing equipment cannot reach these critical parts.

Raw materials must be strictly controlled

For non-standard parts, materials such as 42 chromium molybdenum and 174 stainless steel are often used. When entering the factory, the furnace number and flaw detection report must be checked. In 2023, a factory in Dongguan omitted this process. Then, after about half a year of use, a batch of stainless steel shafts developed micro-cracks. After a final trace, it was discovered that there were problems such as slag inclusions inside the raw materials.

In the procurement contract, the material certificate and mechanical performance indicators need to be fixed, and random inspections will be carried out after the goods arrive. If you encounter a special part, if it requires pre-processing operations such as forging or rolling, you must arrange a production plan with the steel mill in advance. Do not wait for urgent parts to find the required materials temporarily.

Processing operation control parameters

CNC program simulation verification is the bottom line and cannot be skipped directly on the machine. A company in Ningbo that makes gear shafts started rough machining without simulation for the first time in the early 1970s. The entire bar was scrapped due to tool collision, resulting in a loss of nearly 8,000 yuan.

During the operation, the cutting speed, feed rate and depth of cut must be closely monitored. Whenever a tool is replaced, the tool setting operation must be performed again. If vibration or abnormal noise is found, stop the machine immediately.

Don't bet with the hope that "it will be enough to get over it". Only by recording specific parameters and keeping them in files can we truly accumulate technology.

Don’t be formal about quality inspection

It is a routine operation procedure to use a three-dimensional coordinate measuring machine to detect external dimensions, but the geometric tolerance and surface roughness must be checked separately.

In 2024, there was a factory in Shenzhen responsible for the production of medical parts. The measurement results of the dimensions of all the products they produced were all qualified. However, the roughness of the surface did not meet the required standards, which caused the client to directly refuse to receive the goods. The goods were backlogged in the warehouse for forty days.

For unqualified parts, the cause needs to be clearly identified first to see if the tool is worn, the fixture is loose, or there is a deviation in the program. Only after these specific situations have been dealt with and rework completed can subsequent work be continued.

Never simply write a general word like "return as unqualified". The relevant data must be archived in the part number so that when the same part is encountered in the future, the data can be directly called for processing.

Surface treatment and assembly finishing

The processes of electroplating, oxidation and spray painting may seem very simple at first glance. However, as long as the pre-treatment is not done properly, the adhesion strength of the film layer will be directly reduced by half. In 2025, when a factory in Wuhan was processing a batch of aluminum parts, it was discovered that the oil film on the surface could not be completely removed before oxidation. As a result, blistering appeared on the surface of the product in just two weeks, eventually causing the entire batch of products to need to be reworked and repaired.

During the assembly stage, we will verify the overall performance and add inspection points on key mating surfaces. Next, we archive the assembly records. This action is directly related to the specific part number.

In this way, when we need to produce the same type of parts next time, we can directly call the previously accumulated parameter information. In fact, this is exactly what we have accumulated in terms of technology.

When your factory produces non-standard parts, which link is the most time-consuming and most likely to cause quality problems? Please share your views in the comment area. If you find the content useful, please like it and forward it to the masters in the workshop for viewing.