How to control the precision when CNC machining

- Aug 08, 2019-

The content of mold precision includes four aspects: dimensional accuracy, shape accuracy, positional accuracy, and appearance accuracy. Since the mold is divided into two parts, the upper mold and the lower mold, the positional accuracy between the upper and lower molds is the most important among the four kinds of precision.

3. The precision of the mold is for the precision of the product. The high-precision product must be guaranteed by a more high-precision mold. The precision of the mold must be higher than the accuracy of the workpiece by level 2 or above.

Method of improving mold accuracy

1. Precision of mold processing equipment

2. Part accuracy requirements for mold manufacturing

1. Mold material accuracy requirements

Mold steel processing tolerance restraint standard template size fine plate thickness flatness 300X300 +0.005-0±0.005300X500 +0.01-0±0.01500X800+0.01-0.01±0.015800X1200+0.02-0.02±0.022 . The accuracy of the mold parts requires a. The guiding parts that affect the precision of the mold adopt the MISUMI guide column and the guide sleeve series, and the ultra-fine tolerance can be restrained within 0.002mm.

b. The cutting edge forming punching needle adopts the MISUMI standard material: SKD-11 hardness: 60-62HRC cutting edge shape: DREGTH punching needle is usually used for forming the inner hole or cylindrical shape on the product. The precision of the punching needle can be restrained to ±0.01mm, and the special requirement can be about 2um, and the mirror surface is kept.

3. The size of the mold gap is the main basis for mold design and manufacturing accuracy. To ensure the dimensional accuracy and shape position accuracy of the mold production, as well as the product quality (such as the cross-section quality and burr height), the gap between the mold embossing molds must be ensured. .

4. The construction accuracy of the mold requires 1. Guarantee of mold frame accuracy Luo Baihui said that from the perspective of processing and assembly, the accuracy of the formwork mainly includes the following aspects: a. The planar dimensions of the upper and lower templates and the position of the guide holes; b. The flatness and parallelism of the large plane of the template; c. The verticality of the guiding hole to the large plane; d. The perpendicularity between adjacent sides of the template; e. The precision of the cooperation between the guide post and the guide sleeve.

The main methods for guaranteeing the accuracy of the formwork are:

a. After the one-time machining method, that is, the large-plane machining of the template is completed, the upper and lower templates are clamped together, and the planar dimensions and the guide holes of the two templates are processed at one time.

b. One of the four guide holes is offset from the symmetry to ensure the orientation of the mold.

c. Processing reference position (Datum) for calibration processing.

d. Guide column and guide sleeve with high matching precision.

e. Improve the machining accuracy of parts.

2. The guarantee of the accuracy of the punch is considered to be: from the perspective of processing and assembly, the accuracy of the punch mainly includes: a. The shape and dimensional accuracy of the punch; b. The perpendicularity between adjacent sides of the punch.

3. The accuracy of the die ensures that the accuracy of the die mainly includes: a from the perspective of processing and assembly. The dimensional accuracy of the die; b. The perpendicularity between adjacent sides of the die; c. The perpendicularity of the side of the die to the large plane; d. The position of the die.

5. The precision of the forming process ensures that when machining the forming structure, whether it is computer boring, electric spark, wire cutting or ordinary milling machine, the coordinate processing method is adopted. The guarantee of accuracy depends mainly on the accuracy of the machine tool and the accuracy of the operator's calibration and classification. It is believed that, like the guidelines and guiding ideology for establishing an enterprise product quality assurance and management system, the concept of mold precision should also run through the entire process of mold design and manufacturing. In order to ensure the precision requirements of the closed loop of the mold assembly size chain, the process involving the processing and manufacturing of the mold, the outsourcing (including materials, standard parts) and the whole process of mold assembly, trial mold, acceptance, packaging and transportation, to the mold The key aspects and key factors of precision must be strictly controlled and managed.


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We are expert on Custom metal parts, CNC machined parts, precision machining, aluminum machining, CNC machining ,CNC milling, CNC turning processing, precision grinding and so on. 


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Dongguan Lemo Precision Metal Products Co.,Ltd

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Email: amy.chen@lemo-machining.com

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