【Dimensional Accuracy Is Unstable in Mass-Production Press Forming】Die Conditions That Cannot Be Determined from Drawings Alone

In mass production press forming, even when a die is manufactured according to the drawing, the actual product shape and dimensions may not fall within the target values. A drawing is the starting point for die manufacturing, but in order to bring the product shape and dimensions closer to the target values, it is necessary to measure trial products and reflect the measurement results back into die adjustments. In addition, when the cause cannot be clearly identified, it is necessary to check not only the drawing but also the actual production conditions and the problems occurring at the production site.

This article explains why product accuracy may remain unstable even when a die is manufactured according to the drawing, as well as the process of adjusting the die based on trial production results.

Table of Contents

• Even with a die manufactured according to the drawing, the product may not fall within the specified values
• Measurement results alone cannot determine the direction of die adjustment
• FUJILLOY's direct sales system and production-site-based technical support
• FAQ
• Glossary

■　Even with a Die Manufactured According to the Drawing, the Product May Not Fall Within the Specified Values

Dies are designed and manufactured according to the shape and dimensions of the product to be produced. However, even if the die itself is finished according to the drawing, this does not necessarily mean that the product after press forming will have a shape and dimensions within the target values.

This is because the final product is not determined solely by the shape and dimensions of the die. In addition to the hardness and thickness of the material being processed, various factors such as press load, lubrication conditions, and processing speed also affect the forming results.

Therefore, it is necessary not only to check the finished condition of the die, but also to measure the actual processed product in order to determine where deviations from the target values occur and how large those deviations are.

■　Measurement Results Alone Cannot Determine the Direction of Die Adjustment

By measuring trial products, it is possible to identify locations that fall outside the target values and the extent of the deviations. However, measurement results alone may not be sufficient to determine whether the cause lies in the die or in the material and press-forming conditions.

For example, even with the same dimensional deviation, the possible causes differ depending on whether it occurs immediately after production begins or gradually becomes larger during continuous processing. The results may also vary depending on the material lot, the press machine being used, or setup conditions.

To determine the direction of adjustment, it is important to check the following production-site information together with the measured values:

• The process or timing at which dimensional deviation occurs
• Whether dimensions change during continuous processing
• Differences caused by material lots or press machines
• Conditions such as load, lubrication, and processing speed
• Die wear condition and previous adjustment history
• Changes occurring before and after setup changes

By comparing this information, it becomes easier to determine whether the die shape should be modified or the processing conditions should be reviewed. If the die is modified without sufficiently identifying the cause, deviations may occur in other areas, or repeated modification and trial production may become necessary.

Therefore, to maintain stable dimensional accuracy during mass production, it is important not to make decisions based only on drawings or measured values, but to consider the direction of adjustment together with the actual production conditions.

■　FUJILLOY's Direct Sales System and Production-Site-Based Technical Support

This type of decision requires technical support capable of checking actual production conditions in addition to reviewing drawings and measurement results. FUJILLOY (THAILAND) CO., LTD. uses a direct sales system without going through a trading company and receives information about die and product issues directly from customers.

In addition to die drawings and trial product measurement results, the process in which the problem occurs, production conditions, and previous adjustment history are also checked in order to organize the issues from a technical perspective.

When necessary, technical personnel visit the customer's factory to check the actual products and production conditions, identify the causes of dimensional deviations, and consider the direction of die adjustments. A characteristic of the direct sales system is that technical personnel can directly verify the information provided by customers and proceed with the response based on actual processing results at the production site.

If product dimensions remain unstable even after the die has been manufactured according to the drawing, or if you are experiencing difficulties with die adjustment or new die manufacturing, please contact us.

■　FAQ

Q1: Why might a product fail to fall within the specified values even when the die is manufactured according to the drawing?

A1: This is because actual press forming is affected by material properties, processing conditions, applied load, and other factors. Therefore, trial products must be measured and the details of the die adjusted according to the results.

Q2: What information is required when the cause of the problem is unknown?

A2: The die drawing, target product shape and dimensions, trial product measurement results, locations that fall outside the specified values, and problems occurring at the production site are checked.

Q3: Can I consult you even if the drawings or trial products are not yet complete?

A3: Yes. Even if the information is not yet complete, consultation can begin based on the symptoms currently known and the condition of the product. The available information can be organized while considering the measurements or trial production required in the next step.

■　Glossary

• Press Die
  A tool used with a press machine to form material into the required shape.
• Direct Sales System
  A system in which the manufacturer receives inquiries directly from customers and provides sales and technical support.
• Production Engineering
  A department responsible for technical evaluation and proposing die adjustment methods based on information about the product and the production site.

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