1、 Draw mold drawing
It is required to draw according to the national drawing standard, but it is also required to combine the factory standard and the factory customary drawing method not specified by the state. Before drawing the general assembly drawing of the mold, the process drawing shall be drawn and shall meet the requirements of the part drawing and process data. For the size guaranteed by the next process, the words "process size" shall be marked on the drawing. If no other machining is carried out after forming except for repairing burrs, the process drawing is exactly the same as the part drawing. Under the process drawing, it is best to mark the part number, name, material, material shrinkage, drawing proportion, etc. The process drawing is usually on the mold assembly drawing.
1. Draw the general assembly structure drawing
The general assembly drawing shall be drawn in the ratio of 1:1 as far as possible, starting from the cavity, and the main view and other views shall be drawn at the same time.
(1) The general assembly drawing of mould shall include the following contents:
1) Mold forming part structure
2) Structural form of gating system and exhaust system.
3) Parting surface and parting part taking method.
4) Outline structure and all connecting parts, positioning and position of guide parts.
5) Mark the height dimension of the cavity (not mandatory, as required) and the overall dimension of the die.
6) Auxiliary tools (take-off tool, mold unloading tool, correction tool, etc.).
7) Make up the serial numbers of all parts in order and fill in the detailed list.
8) Mark the technical requirements and instructions.
(2) Technical requirements for general assembly of molds:
1) For the performance requirements of some die systems. For example, the assembly requirements of ejector system and sliding block core pulling structure.
2) Requirements for die assembly process. For example, after the mold is assembled, the fitting gap of the parting surface and the fitting surface shall not be greater than the parallelism requirements of the upper and lower parts of the mold, and the size determined by the assembly and the requirements for this size shall be pointed out.
3) Mold use, assembly and disassembly methods.
4) Anti oxidation treatment, die number, lettering, marking, oil seal, storage and other requirements.
5) Requirements for mold test and inspection.
2. Draw all parts drawings
The sequence of drawing parts from the general assembly drawing of the mold shall be: first inside then outside, first complex then simple, first formed parts, and then structural parts.
1) Graphic requirements: it must be drawn to scale, and it is allowed to zoom in or out. The view selection is reasonable, the projection is correct and the layout is appropriate. In order to make the processing patent number easy to understand and easy to assemble, the graphics shall be consistent with the general assembly drawing as far as possible, and the graphics 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 die inclination, then mark the fit dimensions, and then mark all dimensions. On the drawing of non main parts, the fitting dimensions shall be marked first, and then all dimensions shall be marked.
3) Surface roughness. Mark the roughness with the most application on the upper right corner of the drawing, such as "other 3.2" Other roughness symbols are 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, graphic proportion, machining accuracy of free size, technical description, etc., shall be filled in correctly.
2、 Proofreading, drawing review, drawing tracing and drying
(1) Relationship between mould and its parts and plastic part drawing
Whether the material, hardness, dimensional accuracy and structure of molds and mold parts meet the requirements of plastic parts drawings.
(2) Plastic parts
Whether the flow of plastic material flow, shrinkage cavity, weld mark, crack and demoulding slope affect the requirements of plastic parts in terms of service performance, dimensional accuracy and surface quality. Whether the pattern design is insufficient, whether the processing is simple, and whether the shrinkage of forming materials is selected correctly.
(3) Molding equipment
Whether the injection volume, injection pressure and mold locking force are enough, whether there are problems in the installation of the mold, the South core and demoulding of plastic parts, and whether the nozzle of the injection machine is in correct contact with the mouth sleeve.
(4) Mold structure
1) Whether the position of parting surface and finish machining accuracy meet the needs, whether there will be overflow, and whether the plastic parts can be ensured to stay on the side of the mold with ejector after mold opening.
2) Whether the demoulding method is correct, whether the size, position and quantity of the promotion rod and push tube are appropriate, and whether the push plate will be stuck by the core and scratch the formed parts.
3) Mold temperature regulation. Power and quantity of heaters; Whether the flow line position, size and quantity of cooling medium are appropriate.
4) For the method of dealing with the side concave of plastic parts, whether the mechanism of removing the side concave is appropriate, such as whether the sliding block and push rod in the inclined guide pillar core pulling mechanism interfere with each other.
5) Whether the position and size of pouring and exhaust system are appropriate.
(5) Design drawings
1) Whether the placement position of each mold part on the assembly drawing is appropriate, whether it is clearly indicated and whether there is any omission
2) The part number and name on the part drawing, the production quantity, whether the parts are manufactured in-house or purchased, whether they are standard parts or non-standard parts, the matching processing accuracy of parts, the correction processing and allowance at the high-precision dimension 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 shall be correct and shall not be converted by the manufacturer.
4) Check the view position of all part 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 machining performance
Whether the geometric structure, view drawing method and dimension mark of all parts are conducive to processing
(7) Main working dimensions of recalculation auxiliary tools
1) Professional proofreading shall be carried out according to the self proofreading items of the designer in principle; However, we should focus on the structural principle, process performance and operation safety.
2) When drawing, first digest the graphics, draw according to the requirements of national standards, and fill in all dimensions and technical requirements. Self calibration and signature after tracing.
3) Submit the traced base map to the designer for proofreading and signature. It is customary for the relevant technicians of the tool manufacturing unit to review, countersign and check the manufacturing process before sending it to the sun.
(8) Prepare manufacturing process card
1) The technicians of the tool manufacturing unit shall prepare the manufacturing process card and prepare for processing and manufacturing.
2) In the manufacturing process of mold parts, we should strengthen the inspection and focus on the dimensional accuracy. After the mold assembly is completed, the inspector shall inspect according to the mold inspection table. The main thing is to inspect whether the performance of the mold parts is good. Only in this way can the manufacturing quality of the mold be guaranteed.
3、 Mold test and repair
Although the mold design is carried out under the expected process conditions when selecting forming materials and forming equipment, people's understanding is often imperfect. Therefore, after the mold processing is completed, the mold test must be carried out to see the quality of the formed parts. When it is found that it is always wrong, repair the mold to eliminate errors.
There are many kinds of bad phenomena in plastic parts, and the reasons are also very complex. There are both mold reasons and process conditions. The two are often only together. Before mold repair, detailed analysis and research shall be carried out according to the actual situation of the bad phenomenon of plastic parts, and the remedial methods shall be put forward after finding out the causes of the defects of plastic parts. Because the forming conditions are easy to change, the general practice is to change the forming conditions first. When changing the forming conditions can not solve the problem, we can consider repairing the mold.
Repair mold should be more careful, not very sure, do not act rashly. The reason is that once the mold conditions are changed, it can no longer be greatly transformed and restored to the original state.
Whether the performance of the parts is good or not, only in this way can the manufacturing quality of the slang mold be improved.
4、 Sort out data for archiving
After the mold is tested, if it is not used for the time being, the demoulding residue, dust, oil stain, etc. shall be completely removed, coated with butter or other antirust oil or antirust agent, and closed to the storage place for storage.
The technical data generated during the period from the beginning of mold design to the success of mold processing and qualified inspection, such as task book, part drawing, technical specification, mold general assembly drawing, mold part drawing, base drawing, mold design specification, inspection record sheet, mold test and repair record, shall be systematically sorted, bound, numbered and archived according to the regulations. It seems very troublesome, but it is very useful for repairing molds and designing new molds in the future.
