High precision processing, tolerance management, and large boring technology guide

Mold base processing is not just a preprocessing step in high precision injection molds. The precision and structural stability of mold base processing are key base processes that directly affect the mold life, parting surface adhesion, heat transfer efficiency, and cycle time. In particular, in industries that require high cycle production, such as automobiles, home appliances, and electronic components, dimensional precision and tolerance control levels determine production stability.

The mold base is a structure that supports the core and cavity, and at the same time, it is a frame that absorbs thermal expansion and repetitive loads. Therefore, if stress management and floor plan are not properly achieved during the initial mold base processing stage, fine alignment errors can accumulate after assembly, which can lead to flash or cavity eccentricity problems.

Effects of Mold Base Processing on Mold Life and Production Efficiency

Mold base processing is the starting point of mold precision. A leader pin alignment error of 0.01mm will lead to wear imbalance and product dimensional deviation in the long run. In particular, the high precision specification requires ±0.005mm level of management, which depends on the stiffness of the processing facility and the process control system.

Carbon steel series such as S50C and S45C have excellent processability, but internal residual stress can be formed during cutting and milling. On the other hand, freehand steel such as P20 and KP4M has high hardness, so cutting conditions and tool management are key factors in securing dimensional precision. If mold base processing strategy is not established to meet material properties, it can lead to shorter mold life and increased repetitive maintenance cost.

Mold base process sequence: from cutting materials to large boring

Cutting and Stress Relief of Raw Materials

Mold base processing starts with cutting raw materials. Heat and mechanical deformation generated during cutting leave residual stress, which can lead to warping during subsequent processing steps.

For large mold base processing, it is recommended to perform post-cutting stress relief or stress relief heat treatment and to ensure a certain stabilization time, which is an essential step for maintaining dimensional precision and ensuring long-term structural stability.

Grinding 6 faces and securing reference faces

Six-side grinding forms the basis of mold base processing. By polishing the upper, lower, left, and right front surfaces to secure floor plan and right angles, the reference plane for subsequent MCT processing is set.

High precision mold base processing aims for a floor plan of ±0.01mm, and for large plates, temperature management considering the coefficient of thermal expansion is required. Large room temperature deviations can lead to dimensional errors.

MCT machining and precision hole machining

In the MCT processing stage, guide post hole, return pin hole, coolant line processing are performed. At this time, the coaxiality, straightness, and distance error between holes are the key management items.

High rigidity equipment such as Makino and Mazak are suitable for high precision mold base processing in terms of vibration suppression and repetition precision. Cutting oil pressure and tool wear management are important in the Deep Hole drilling process, and poor straightness of the coolant hole can lead to leakage or cooling imbalance.

Accurate alignment with large boring

The large-scale boring process determines the alignment accuracy of the guide post holes. The combination of high-rigid boring equipment and precision measurement equipment is essential because even minute eccentricity can lead to poor alignment after assembly on large plates.

Criteria for Tolerance Management of High-Precision Mold Base Processing

General specification mold base processing requires ±0.01mm of dimensional precision, and high specification projects manage up to ±0.005mm.

This requires securing time for thermal stabilization during processing, correcting tool wear, and maintaining a constant temperature environment. The accuracy of the measuring equipment alone does not complete the tolerance management, and a strategy that considers dimensional stability is required from the process design stage.

Cases of poor mold base processing and improvement strategies

In the actual site, there was a case of MCT processing without sufficient stress removal. After assembly, the parting surface was slid, leading to repeated flash problems.

The process was re-arranged in order of cutting → stress removal → stabilization → six-sided polishing → MCT processing → large bore, and by introducing a total inspection by CMM, the alignment accuracy within ±0.008mm has not been repeated since.

As such, the quality of mold base processing varies greatly depending on the process sequence and stress management strategy.

Factors to consider when selecting a mold base processing company

When requesting high-precision mold base processing, the following factors should be comprehensively reviewed rather than simple unit price comparison.

• Possession of large boring facilities

• Stiffness and repeatability of MCT equipment

• Can CMM-based inspection report be provided

• Processing experience based on material characteristics such as S50C, P20, etc

• Delivery optimization system and process parallelization capabilities

In particular, companies that provide Inspection Reports are highly reliable in that they document the tolerance management system.

SG MOLD is performing non-standard mold base processing based on more than 200 CNC and MCT facilities and large processing facilities, and provides full CMM inspection and inspection report before shipment. Through the Seoul and Daegu offices and Hwaseong A/S response system, we are strengthening technical communication with Korean customers.

Mold Base Processing FAQ

To what level is the precision of mold base processing possible?
Generally, it is around ±0.01mm and can be managed up to ±0.005mm in high-precision specifications.

How long does it take to process the large mold base?
It depends on the specifications and size, and it can be optimized for delivery depending on whether the process is parallelized or the material is ready.

What is the difference between S50C and P20 processing?
S50C has excellent workability, but stress management is important, and P20 has high hardness, so cutting conditions and tool management affect dimensional stability.

Conclusion: Strategic mold base processing determines mold quality

Mold base processing is not a simple processing process, but a strategic step in determining mold life and production stability. High precision mold production is possible when stress removal, tolerance management, thermal deformation response, and large Boring alignment accuracy are systematically secured.

If you need a drawing-based technical review or RFQ consultation, please share the required precision and delivery conditions so that the best mold base processing strategy can be suggested through the pre-technical analysis. The higher the precision, the more the process design in the initial stage determines the long-term quality stability.