Plastic mold processing technology summary

Plastic mold processing technology summary

In order to ensure the rationality and consistency of the mold making process, optimize the processing technology, and improve the progress of mold making, each mold factory generally formulates the process standards suitable for the factory. This article provides a standard for reference.

Plastic mold processing

Craftsman craft card

When the craftsman has programmed the craft card, the processing allowance, the orientation of the reserved amount, the roughness requirements and the precautions should be specified in the process card.

Principles for the processing process card: Under the premise of ensuring accuracy and quality, equipment with high processing efficiency is preferred. The processing efficiency of milling machines, CNC machines and grinding machines is faster than wire cutting and electric pulse, especially the electrical pulse processing efficiency is the slowest. The dimensions on the drawings cannot be changed at will (only the technician can change).

2. Processing allowance principle

The workpiece needs heat treatment processing. Before the heat treatment, the shape of the material preparation is 0.25mm. The mold core and the insert need CNC roughing part. The allowance for single side is 0.2mm. The rough milling machine has a rough milling shape. The remaining allowance is 0.3-0.5mm. After the wire is cut, the workpiece processed by the grinding machine is required. The forming part is reserved for 0.05mm on one side, and the grinding allowance is 0.1mm in the shape of the open side. CNC finishing and mirroring after electric pulse Polished, leaving a 0.03mm polishing allowance on one side.

3. Processing accuracy requirements

The manufacturing precision of the mold size should be in the range of 0.005~0.02mm; the verticality should be in the range of 0.01~0.02mm; the coaxiality should be in the range of 0.01~0.03mm; the upper and lower planes of the moving and fixed mold parting surface The parallelism is required to be in the range of 0.01 to 0.03 mm.

After clamping, the gap between the parting surfaces is smaller than the overflow value of the formed plastic. The parallelism of the other template mating surfaces is required to be in the range of 0.01 to 0.02 mm; the matching precision of the fixed part is generally in the range of 0.01 to 0.02 mm; if the small core does not have the insertion requirement or the size is small, it may take 0.01 to 0.02 mm bilaterally. The clearance fit is matched; the matching precision of the sliding part is generally selected from three types: H7/e6, H7/f7, and H7/g6.

Note: If there is an insert on the mirror surface that is attached to the step, the fit should not be too tight. Otherwise, when the insert is knocked from the front to the back, the tool used for tapping is easy to break the mirror surface. If it does not affect the product size, it can be taken from both sides. 0.02mm clearance fit.

Plastic mold processing

4. Principle of CNC removal of electrodes

The mold cavity core should first disassemble the main body electrode, then disassemble the other main electrode, and finally remove the local electrode; the fixed-mode appearance electrode should consider the overall processing, and the place where the CNC clear angle is not enough, use the wire cutting angle to fix the mold The appearance is complete and there are no joints; the ribs, ribs and columns with different depths of the moving mold can be processed together on one electrode as much as possible; the deeper ribs should be made into inserts, and the electrodes should be made separately. In order to prevent carbon from accumulating during the electric pulse; the movable mold electrode should not be cut by the CNC after cutting the wire. If necessary, the electrode should be disassembled or directly cut by wire; the ribs and bars of the moving die or the column The interval is more than 35mm, which should be done separately to save copper material.

Large electrode rough machining spark position is unilateral 0.3mm, finishing spark position is unilateral 0.15mm; general electrode rough machining spark position is unilateral 0.2mm, finishing spark position is unilateral 0.1mm; small electrode rough machining spark position Make a single side 0.15mm, and finish the spark position to make a single side 0.07mm.

5. CNC machining principles

The mold core and insert need CNC open part, and the margin is 0.2mm on one side. After heat treatment, the workpiece must be CNC finished. If the appearance of the product is allowed, the CNC can finish the mold cavity core in place, and the CNC is preferred. Processing, such as the electrode that can not be processed in place, is processed by electric pulse.

6. Dynamic and static mold processing technology

1) preparation materials;
2) Milling machine processing: drilling water hole (the distance between the water hole plug and the horizontal water hole is 3-4mm), threading hole, drilling, tapping screw hole, drilling, hinge pinhole, mold number, reference angle Give up the floor;
3) CNC machining: rough machining;
4) Heat treatment: indicate hardness requirements;
5) Grinding machine processing: grinding six-sided square ruler, the shape is fixed by the frame size (if the mold core is one piece, the outer dimension is 0.03mm-0.05mm than the drawing size. If the mold core is two pieces, then the two pieces are molded. The outer dimensions of the upward direction are added by 0.03mm-0.05mm than the drawing size, ⊥0.01, ∥0.01, and the part that can be formed by the grinding machine must be ground and formed;
6) If you want CNC finishing of the mold, arrange CNC finishing, such as the font and font number of the cavity to be engraved;
7) Wire cutting processing: middle wire processing insert hole, inclined top hole, thimble hole, boring hole, etc.;
8) EDM: processing according to drawings and pulse instructions;
9) Polishing: The roughness and requirements of polishing are written on the process card. The polished area is marked with a marker on the workpiece. If there is a mirror, the cycle is not enough, and the test die can be roughed before being finely polished.
10) assembly;
11) Test mode.

7. Main body insert processing technology

1) Preparation materials: The craftsman defines whether the workpiece is processed in one piece or in multiple pieces according to the size and shape of the workpiece. If multiple pieces are processed together, the craftsman needs to plan the processing of the workpiece;
2) Milling machine processing: The fitter will process according to the workpiece drawing or the layout drawing of the craftsman, drilling the water hole (the distance between the water hole plug and the horizontal water hole is 3-4mm), threading the hole, drilling, Tap the screw hole, drill, hinge pinhole, the opening of the molding is thick, the mold number, the hanging table gives way;
3) CNC machining: If CNC machining is required, arrange CNC roughing;
4) Heat treatment: indicate hardness requirements;
5) Grinding machine processing: grinding the six-face square, the part that can be formed by the grinding machine must be ground and formed;
6) For CNC finishing workpieces, arrange CNC finishing, such as inserts with fonts and model numbers to be engraved;
7) Wire cutting processing: middle wire processing insert hole, inclined top hole, thimble hole, etc.;
8) EDM: processing according to drawings and pulse instructions;
9) Polishing: The roughness and requirements of polishing are written on the process card. The polished area is marked with a marker on the workpiece. If there is a mirror, the cycle is not enough, and the test die can be roughed before being finely polished.
10) assembly;
11) Test mode.

8. Shaped insert processing technology:

Process 1:
1) Wire cutting processing: the middle wire cutting dimension is cut (A/B view), the pull piece, the thickness is left to grind the grinding machine, and the forming part is rough;
2) Grinding machine processing: grinding thickness, slope, molding;
3) Electrical discharge machining;
4) Polishing processing.

Process 2:
1) Wire cutting processing: middle wire cutting shape, insert hole, thimble hole, size cutting (C view), hanging table and forming place open;
2) Grinding machine processing: grinding height, hanging table, slope, molding;
3) Electrical discharge machining;
4) Polishing processing.

9. Simple insert processing technology

1) Wire cutting processing: fast wire cutting shape residual grinding machine (A/B view), pull-tab, thickness residual grinding machine;
2) The dimensions are fixed, the grinding table, the slope, and the molding;
3) Electrical discharge machining;
4) Polishing processing.

10. Round insert processing technology

1) Centerless grinding: the dimensions are fixed;
2) Grinding machine processing: clearing the corner at the hanging platform;
3) Wire cutting processing: fast wire cutting length (single side 0.1mm grinder allowance), cutting pin hole, vent hole;
4) Grinding machine processing: grinding length, molding.

11. Inclined top processing

1) Wire cutting processing: the shape of the middle wire is cut, the head is left to the remaining amount of the insert surface, the remaining dimensions are ground, the thickness of the pull piece is left, and the groove is opened to make the grinding machine;
2) Grinding machine processing: grinding thickness, I-shaped groove;
3) assembly;
4) pulse;
5) polishing;
6) Milling machine oil groove.

12. Inclined top seat processing technology

1) Fixture stock: The height dimension is reserved for 1.5mm on both sides, the width dimension is reserved for 0.5 mm on both sides, and the length direction is reserved for 5 mm on both sides.
2) Milling machine processing: drilling and tapping screw holes;
3) heat treatment processing;
4) Grinding machine processing: grinding six-sided square ruler, width dimension grinding;
5) Wire-cutting fast-wire processing I-shaped groove, pull-tab, thickness residual grinding machine, height dimension is 1.2 mm;
6) Grinding machine processing: The outer dimensions of the grinding machine are matched with the ejector plate and the height is 1mm.

Plastic mold processing

13. Inclined top guide block processing technology

1) Line cutting processing: fast wire cutting shape, leaving a grinding machine reserved;
2) Grinding machine processing: grinding six-sided square feet, the dimensions are ground;
3) Milling machine processing: threading holes, screw holes;
4) Wire cutting processing: fast wire cutting oblique guiding hole.

14. Slider seat processing technology

1) preparation materials;
2) Grinding machine processing: grinding six-sided square feet, the dimensions are ground;
3) Milling machine processing: drilling through the wire hole, drilling and tapping the screw hole;
4) Wire cutting processing: fast wire processing oblique guide column hole;
5) CNC finishing: the size of the forming part is milled.

15. Briquetting process

1) preparation materials;
2) Milling machine processing: drilling screw through hole, forming part is thick (single side reserved 0.3-0.5, grinding machine);
3) Grinding machine processing: grinding six-sided square ruler, the dimensions are fixed and formed.

16. Locking block processing technology

1) preparation materials;
2) Grinding machine processing: grinding six-sided square feet, the dimensions are ground;
3) wire cutting processing; fast wire forming;
4) Milling machine processing: drilling and tapping screw holes.

17. Principle of ejector hole processing

The Φ3 or above (including Φ3, Φ4, Φ5, Φ6) boring hole is machined by drilling machine, reaming; Φ3 or below or non-standard ejector hole, using wire cutting processing, bottom avoidance.

18. Principle of threading hole processing

When all kinds of holes need to be cut, when the inner wall circumference is larger than Φ3 or more (including Φ3), the wire holes must be drilled.

19. The processing of the trademark and the need for a mirror-shaped mold

1) After the CNC is finished milling, the mark is left at the mark;
2) Wire cutting in the middle of wire processing: trademark insert hole;
3) EDM: the depth of the hanging platform;
4) With the brand core, the installation fixture;
5) The balance of the trademark is pulsed flat; 6 polished.

20. Formwork processing technology

1) Milling machine processing: inner frame chamfering, drilling screw hole, thimble hole, waterway hole, gate cup through hole, inclined top hole through hole;
2) CNC machining: milling nozzle cup countersunk, inclined top seat hole, guide block hole, row position groove, hot runner die A plate requires CNC machining, die foot lettering processing.

21. Back plastic mold processing technology for the mounting frame with grid ribs

The processing of the mold ribs after such a mounting frame selects different processing techniques according to different mold types.
1) For a type of mold, we directly use the integral electrode to ensure the uniformity of the product;
2) When the processing technology of a non-type mold is selected, it can be adjusted according to the actual processing amount. The electrode can be split or integrated. If the rib is a through groove, the wire can be cut first and then the grinder is refined.

22. Need to cut the fixture or electrode, batch pulsed workpiece

For some workpieces (such as the core of the multi-function two-plug jack), a wire cutting jig or an electrode is required. The processing flow of the batch pulsed workpiece is as follows:
1) CNC out of the map;
2) The wire cutting drawing is processed by a size fixture or an electrode;
3) After the wire cutting process is completed, if the electrode still needs CNC machining, the electrode is handed over to the CNC, and the jig is transferred to the fitter;
4) CNC machining the electrode and discharging the discharge diagram;
5) Pulse processing;
6) Polishing.

23. Support column height calculation

The height of the support column below 3030 is 0.08-0.1mm higher than the mold foot, 3030 is higher than 0.1mm, 3535 is 0.1-0.12mm higher, and 3535 is higher than 0.12-0.15mm.

24. Thimble processing technology

Φ2 and above thimble cutting machine cutting length to leave the remaining amount of grinding machine, grinding machine processing length and size grinding (tools self-processing); Φ2 below ejector cutting processing size cutting. The flat thimble and the cylinder are made of wire cutting length and residual grinding machine; the grinding machine is processed, and the length is fixed.

These are Plastic mold processing technology summary

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