Generally, mold design task book is proposed by part craftsman based on task book of molded part. Mold often implement process of collecting, analyzing, digesting original data, drawing drawings and final assembly drawings, proofreading, reviewing drawings, tracing drawings, sending photos, making all parts drawings, testing molds, repairing molds, and collating data for archiving to achieve mold manufacturing.

 

In order to ensure rationality and consistency of mold manufacturing process, optimize processing process, and improve progress of mold manufacturing, each mold factory generally formulates a process standard suitable for its factory. This article provides a reference standard, starting from automotive industry, lists some of more important auto parts mold and processes.

 

When craftsman compiles crafting card, process reserve, orientation of reserve, roughness requirements, and precautions should be specified in craft card in detail.
Principles of writing process cards: On premise of ensuring accuracy and quality, equipment with high processing efficiency is preferred. Milling, CNC, and grinding machines have faster processing efficiency than wire cutting and electric pulse, especially the slowest electric pulse processing efficiency. Dimensions on drawing cannot be changed at will.

 

Note: All mold plates have been finished in place, water line can be processed after back to factory.
After mold back factory, requires for fitter is:
1. Whether reference planes of A and B plates are flush, whether reference angle is right angle;
2. Whether opening and closing of guideposts and guide sleeve is smooth;
3. Are mold screws and perforations standard?
4. Whether lower guide post and return pin are smooth;
5. Whether mold plate is deformed or black.

 

 

Note: Red area of A and B plates has a rough thickness of 3MM, remaining surfaces need to be processed in place.

1. For workpieces that need to be heat treated, size of external stock size needs to add 0.25mm of grinding machine margin on one side before heat treatment;
2. For parts that require CNC rough machining of mold cores and inserts, leave a margin of 0.2mm on one side;
3. When rough milling shape with a milling machine, margin on one side is 0.3-0.5mm. For workpieces that need to be processed by a grinder after wire cutting, a single side of forming part need to be reserved for 0.05mm, a grinding allowance of 0.1mm need to be reserved on one side for roughing process of shape
4, Mirror polishing after CNC fine finishing electric pulse, leaving a polishing margin of 0.03mm on one side.

Manufacturing accuracy of mold size should be within range of 0.005 to 0.02mm. Perpendicularity should be within range of 0.01 to 0.02mm. Coaxiality should be within range of 0.01 to 0.03mm. Parallelism requirement of upper and lower planes of moving and fixed mold parting surfaces should be within range of 0.01 to 0.03 mm.
After mold is closed, gap between parting surfaces is smaller than overflow edge value of formed plastic. Parallelism requirement of fitting surfaces of other mold plates is required to be within range of 0.01 to 0.02 mm. Fitting accuracy of fixed part is generally selected to be within range of 0.01 to 0.02 mm; if small core has no fitting requirements or has little effect on size, it is preferable to have a bilateral range of 0.01 to 0.02 mm. Clearance fit of sliding part is generally selected as H7/e6, H7/f7, H7/g6.
Note: If there is a stepped insert on mirror surface, fit must not be too tight, otherwise tool used to strike will easily damage mirror surface when insert is knocked back from front. If it does not affect size of product, it is advisable to double-sided 0.01~0.02mm clearance fit.

 

Mold cavity core should first disassemble appearance main electrode, then dismantle other main electrode, and finally dismantle local electrode. Fixed mold appearance electrode should consider overall processing. Where CNC is not cleared, wire cutting is used to ensure that appearance of fixed mold is complete and there are no joint marks. Reinforcement ribs, ribs, and pillars with small difference in depth of movable mold can be processed on one electrode as much as possible. Deeper ribs need to be inserted on electrode side to prevent carbon deposits during electric pulses. Do not try not to use wire cutting to clear corners of movable mold electrode after CNC milling. If necessary, disassemble electrode or directly use wire cutting. Space between ribs or pillars of movable mold should be more than 35mm, which should be done separately to save copper material.
Large electrode rough machining spark position is unilateral 0.3mm, fine machining spark position is unilateral 0.15mm; general electrode rough machining spark position is unilateral 0.2mm, fine machining spark position is unilateral 0.1mm; small electrode rough machining spark position is unilateral 0.15mm, finishing spark position is unilateral 0.07mm.

 

Mold cores and inserts need to be rough processed by CNC, with a margin of 0.2mm on one side. For workpieces that need CNC finishing after heat treatment, if appearance of product allows, mold cavity cores that CNC can finish in place are preferentially processed by CNC. Use electric pulse to process places that cannot be processed in place.

 

1) Prepare materials;
2) Milling processing: drilling water transporting holes (distance between deepest end of water transporting plug and horizontal water transporting hole is 3-4mm), threading holes, drilling and tapping screw holes, drilling and pinholes, mold number, reference angle, and concession on platform;
3) CNC machining: rough machining;
4) Heat treatment: indicate hardness requirements;
5) Grinding: Grinding a six-sided square ruler, shape is ground to size of frame (if mold core is one piece, overall size is 0.03mm-0.05mm less than drawing size. if mold core is two, shape dimensions of two mold cores are added together and size is 0.03mm-0.05mm less than drawing size.), parts that can be shaped by grinding machine must be ground and shaped;
6) If CNC core machining is required, arrange CNC finishing. For example, cavity has fonts and mold numbers that need to be processed by lettering;
7) Wire cutting processing: Medium wire processing insert holes, oblique top holes, thimble holes, pinholes, etc .;
8) EDM: single processing according to drawings and pulse instructions;
9) Polishing process: write roughness and requirements of polishing on process card, mark polished area on workpiece with a marker. If there is a mirror requirement and cycle is too late, it can be rough polished first and then fine polished;
10) Assemble and test mold.

 

1) Prepared materials: Craftsman defines whether to process a single piece or multiple pieces together according to size and shape of the workpiece. If multiple pieces are processed together, craftsman needs to map processing position of workpiece;
2) Milling process: Fitter performs processing according to workpiece drawing or combination drawing issued by technician, drilling water transporting holes (distance between deepest end of water transporting plug and horizontal water transporting hole is 3-4mm), threading holes, drilling and tapping screw holes, drilling and pinholes, mold number, reference angle, and concession on platform;
3) CNC machining: if CNC rough machining is required, arrange CNC rough machining;
4) Heat treatment: indicate hardness requirements;
5) Grinding processing: Grinding a six-sided square ruler, part that can be shaped by grinding machine must be ground and formed;
6) For CNC-finished workpieces, arrange CNC finishing. If inserts have fonts and mold numbers, they need to be engraved;
7) Wire-cutting processing: middle wire processing insert holes, oblique top holes, thimble holes, etc .;
8) EDM: single processing according to drawings and pulse instructions;
9) Polishing process: write roughness and requirements of polishing on process card, use a marker to mark polished area on workpiece. If there is a mirror requirement and cycle is too late, it can be rough polished first and then fine polished;
10) Assemble and test mold.

 

1) Wire-cutting processing: Medium wire cutting with exact dimensions (A/B view), pull-tab, grinder with thickness allowance, and roughing at molding place;
2) Grinding machine processing: grinding thickness, slope, forming;
3) EDM;
4) Polishing.

1) Wire cutting processing: cut shape, insert hole, and pin hole with middle wire, cut size accurately (view C), rough process for hanging platform and molding area;
2) Grinding machine processing: grinding height, hanging table, slope, forming;
3) EDM;
4) Polishing.

1) Wire cutting processing: use middle wire cutting shape, head is left to grind and match remaining surface, remaining dimensions are ground accurately.
2) Grinding process: grinding thickness, I-groove;
3) Assembly;
4) Pulse;
5) Polishing;
6) Milling oil groove.

1) Fitter preparation: 1.5mm on both sides of height dimension, 0.5 mm on both sides of width dimension, and 5 mm on both sides of length dimension to facilitate wire cutting and clamping;
2) Milling process: drilling and tapping screw holes;
3) Heat treatment processing;
4) Grinding process: Grinding of six-sided square ruler, accurate grinding of width and size;
5) Wire cutting fast wire processing I-groove standard, pull-tab, thickness allowance for grinding processing, height dimension is plus 1.2 mm;
6) Grinding process: Grind external dimensions with grinding machine, fit ejector plate, and height dimension is plus 1mm.

 

1) Prepare materials;
2) Milling process: Drilling screws through holes, roughening forming place (0.3-0.5 for one side, grinder);
3) Grinding process: Grinding on a six-sided square ruler, accurate shape.

1) Prepare materials;
2) Grinding process: Grinding on a six-sided square ruler, dimensions are accurate;
3) Wire cutting processing; fast wire molding;
4) Milling process: drilling and tapping screw holes.

 

Above Φ3 (including Φ3, Φ4, Φ5, Φ6) jack holes are processed with milling machine for drilling and reaming; below Φ3 or non-standard jack holes, wire cutting is used to avoid bottom.

When various holes need to be processed by wire cutting and circumference of inner wall is larger than or equal to Φ3 (including Φ3), hole must be drilled through.

Remainder of thimble cutting length above Φ2 is used for grinding, grinding processes length and size of grinding standard (machined by fitter). Size of thimble below Φ2 be processed accurately. Flat pin and barrels are machined with a wire cutting length and a margin grinder; grinder is used to grind length and size accurately.