1.Performance requirements for some systems of precision plastic mould. For example, the assembly requirements of ejection system and sliding block core pulling structure.
2.Requirements for assembly process of precision plastic mould. For example, the joint clearance of the joint surface of the parting surface after the die assembly shall not be greater than the parallelism requirements of the upper and lower parts of the die, and the size determined by the assembly and the requirements for the size shall be pointed out.
3.Mold use, assembly and disassembly methods.
4. Anti oxidation treatment, mold number, lettering, marking, oil seal, storage and other requirements.
5.Requirements for mold test and inspection.
6.Drawing all parts
Precision plastic mold
The order of drawing the part drawing from the die assembly drawing shall be: first inside, then outside, first complex, then simple, first forming parts, then structural parts.
1. Graphic requirements: be sure to draw in proportion, and allow to enlarge or shrink. The view selection is reasonable, the projection is correct and the layout is proper. In order to make the processing patent number easy to understand and easy to assemble, the figure shall be consistent with the general assembly drawing as much as possible, and the figure shall be clear.
2. The dimensions shall be unified, centralized, orderly and complete. The order of dimensioning is: first mark the dimensions of main parts and the inclination of the die, then mark the matching dimensions, and then mark all dimensions. On the drawings of non main parts, the matching dimensions shall be marked first, and then all dimensions shall be marked.
3. Surface roughness. Mark the most applied roughness on the upper right corner of the drawing, such as "the rest 3.2". "Other roughness symbols shall be marked on each surface of the part.
4. Other contents, such as part name, die drawing number, material brand, heat treatment and hardness requirements, surface treatment, drawing proportion, machining accuracy of free size, technical description, etc., shall be filled in correctly.
7.proofread, review and trace
A. The contents of self proofreading are:
1. Relationship between mold and its parts and plastic drawing
Whether the material, hardness, dimensional accuracy, structure, etc. of the mold and mold parts meet the requirements of the plastic drawing.
2. Plastic parts
Whether the flow, shrinkage cavity, weld mark, crack and demoulding slope of plastic material flow affect the requirements of the use performance, dimensional accuracy and surface quality of plastic parts. Whether the pattern design is insufficient, whether the processing is simple, and whether the shrinkage of the molding material is correct.
3. Molding equipment
Whether the injection volume, injection pressure and mold locking force are enough, whether there are problems in mold installation, South core of plastic parts and demoulding, and whether the nozzle of the injection machine contacts the cuff correctly.
4. Mold structure
① Whether the position of parting surface and finish machining accuracy meet the requirements, whether overflow will occur, and whether the plastic parts can be ensured to stay on the side of the mold with ejection device after opening the mold.
② . whether the demoulding method is correct, whether the size, position and quantity of the extension rod and push tube are appropriate, whether the push plate will be stuck by the core, and whether the formed parts will be scratched.
③ . mold temperature adjustment. Whether the power and quantity of the heater and the flow line position, size and quantity of the cooling medium are appropriate.
④ . the method of processing the side concave of plastic parts, and whether the mechanism of removing the side concave is appropriate, such as whether the slide block and push rod in the core pulling mechanism of inclined guide pillar interfere with each other.
⑤ . whether the position and size of pouring and exhaust system are appropriate.
5. Design drawings
① . whether the positions of mold parts on the assembly drawing are proper, clearly indicated and omitted
② . whether the part number, name, manufacturing quantity, internal manufacturing or outsourcing of parts, standard parts or non-standard parts, parts matching processing accuracy, correction processing and allowance of high-precision dimensions of molded plastic parts, and whether the material, heat treatment, surface treatment and surface finishing degree of mold parts are clearly marked and described.
③ . working dimensions and matching dimensions of main parts and formed parts. The size figures should be correct and not be converted by the producer.
④ . check the view position of all parts drawings and general assembly drawings, whether the projection is correct, whether the drawing method conforms to the drawing national standard, and whether there are missing dimensions.
6. Check processing performance
(is the geometry, view drawing and dimension mark of all parts conducive to machining)
7. Main working dimensions of recalculation auxiliary tools
B. In principle, the professional proofreading shall be carried out according to the designer's self proofreading items, but it shall focus on the structural principle, technological performance and operation safety.
When drawing, first digest the figure, draw according to the requirements of national standard, and fill in all dimensions and technical requirements. Check and sign after tracing.
C. The traced base drawing shall be submitted to the designer for proofreading and signature. The usual practice is that the relevant technical personnel of the tool manufacturing unit shall review, countersign and check the manufacturing process, and then it can be sent to the sun.
D. Prepare manufacturing process card
Technical personnel of tool manufacturing unit shall prepare manufacturing process card and prepare for processing and manufacturing.
In the manufacturing process of die parts, we should strengthen the inspection and focus on the dimensional accuracy. After the mold assembly, the inspector shall inspect according to the mold inspection table, mainly to inspect whether the performance of the mold parts is good, only in this way can the manufacturing quality of the mold be slang.
8. Mold test and repair
Although it is in the selection of molding materials and equipment, mold design is carried out under the expected process conditions, but people's understanding is often imperfect, so it is necessary to carry out mold test after the completion of mold processing to see the quality of the formed parts. After finding out that it is always later, correct the wrong mold.
There are many kinds of defects in plastic parts, and the causes are very complex. There are mould reasons
