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One, draw the mold diagram
It is required to draw in accordance with the national drawing standards, but it is also required to combine the factory standards and factory custom drawing methods not specified by the country. Before drawing the mold assembly drawing, the process drawing should be drawn, and it should meet the requirements of the part drawing and process data. The size guaranteed by the next process should be marked with the words "process size" on the drawing. If after forming, apart from repairing the burr, no other machining is performed, then the process drawing is exactly the same as the part drawing.
It is better to mark the part number, name, material, material shrinkage rate, drawing ratio, etc. under the process drawing. Usually the process drawing is on the mold assembly drawing.
1. Draw the assembly structure diagram
When drawing the assembly drawing, try to use a ratio of 1:1, first draw from the cavity, and draw the main view and other views at the same time.
(1) The mold assembly drawing should include the following
1) The structure of the mold forming part
2) The structure of the pouring system and exhaust system.
3) Parting surface and way of parting and taking parts.
4) Shape structure and all connecting parts, positioning and guiding parts.
5) Mark the height of the cavity (not mandatory, as required) and the overall size of the mold.
6) Auxiliary tools (tools for picking and unloading molds, correction tools, etc.).
7) Code all the part numbers in order and fill in the detailed list.
8) Mark technical requirements and instructions for use.
(2) The technical requirements of the mold assembly drawing
1) Performance requirements for certain systems of molds. For example, the assembly requirements for ejector system and slider core pulling structure.
2) Requirements for mold assembly process. For example, after the mold is assembled, the bonding gap of the bonding surface of the parting surface should not be greater than the parallelism requirements of the upper and lower sides of the mold of 0.05mm, and indicate the size determined by the assembly and the requirements for this size.
3) Mold use, assembly and disassembly methods.
4) Anti-oxidation treatment, mold numbering, lettering, marking, oil seal, storage and other requirements.
5) Requirements related to mold trial and inspection.
2. Draw all parts diagram
The sequence of disassembling and drawing parts from the mold assembly drawing should be: first inside and then outside, first complicated and then simple, forming parts first, then structural parts.
(1) Graphic requirements
It must be drawn to scale, allowing zoom in or zoom 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 should be as consistent as possible with the assembly drawing, and the graphics should be clear.
(2) The dimensioning requirements are unified, centralized, orderly and complete
The order of dimensioning is: first mark the main part dimensions and the draft angle, then mark the matching dimensions, and then mark all the dimensions. Mark the mating dimensions on the non-main parts drawing first, and then mark all the dimensions.
(3) Surface roughness
Mark the most used roughness on the upper right corner of the drawing, such as "Remaining 3.2." Other roughness symbols are marked on each surface of the part.
(4) Other content
For example, the part name, mold drawing number, material designation, heat treatment and hardness requirements, surface treatment, graphic ratio, free size processing accuracy, technical description, etc. must be filled in correctly.
2. Proofreading, reviewing, tracing, sending photos
Self-proofreading content:
(1) The relationship between the mold and its parts and the plastic drawing
Whether the material, hardness, dimensional accuracy, structure, etc. of the mold and mold parts meet the requirements of the plastic parts drawings.
(2) Plastic parts
Whether the flow of plastic material flow, shrinkage cavity, weld mark, crack, demoulding angle, etc. affect the performance, dimensional accuracy, surface quality and other requirements of plastic parts. Whether the pattern design is insufficient, whether the processing is simple, and whether the shrinkage rate of the molding material is selected correctly.
(3) Forming equipment
Whether the injection volume, injection pressure, and clamping force are enough, whether there is any problem with the installation of the mold, the south core of the plastic part, and the demoulding, and whether the nozzle of the injection machine and the nozzle sleeve are correctly contacted.
(4) Mould structure
1) Whether the position of the parting surface and the precision of the finishing process meet the needs, whether there will be flashing, and whether the plastic parts can be guaranteed to stay on the side of the mold with the ejector device after the mold is opened.
2) Whether the demolding method is correct, whether the size, position, and quantity of the promotion rod and push tube are appropriate, whether the push plate will be jammed by the core, and will it cause scratches on the molded parts.
3) Regulating mold temperature. The power and quantity of the heater; whether the location, size, and quantity of the flow line of the cooling medium are appropriate.
4) The method of processing the undercut of plastic parts, and whether the mechanism for removing the undercut is appropriate, such as whether the slider and the push rod in the inclined guide column core pulling mechanism interfere with each other.
5) Whether the position and size of the pouring and exhaust system are appropriate.
(5) Design drawings
1) Whether the placement of each mold part on the assembly drawing is appropriate, whether it is clearly expressed, and whether there is any omission
2) The part number, name, production quantity, in-house or outsourcing of the part on the part drawing, standard or non-standard part, matching processing accuracy of the part, correction processing and margin at the high-precision dimension of the molded plastic part, Whether the material, heat treatment, surface treatment, and surface finishing degree of the mold parts are marked and clearly described.
3) The working size and matching size of main parts and forming parts. The size figures should be correct and do not cause the manufacturer to convert.
4) Check the view positions of all parts drawings and assembly drawings, whether the projection is correct, whether the drawing method meets the drawing national standard, and whether there is any missing size.
(6) Check processing performance
Whether the geometric structure, view drawing method, size mark, etc. of all parts are conducive to processing
(7) The main working size of recalculation auxiliary tools
1) Professional proofreading is carried out in principle according to the designer's self proofreading project; however, it should focus on structural principles, process performance and operational safety.
When drawing, you must first digest the graphics, draw according to the requirements of the national standard, and fill in all the dimensions and technical requirements. Self-study and sign after the scan.
2) Submit the sketched base map to the designer for proofreading and signing. The customary practice is to review by the relevant technical personnel of the tool manufacturing unit, countersign and check the manufacturing process, and then send it out.
(8) Compile manufacturing process cards
The technical staff of the tool manufacturing unit compiles the manufacturing process card and prepares for processing and manufacturing.
In the manufacturing process of mold parts, inspection should be strengthened, and the focus of inspection should be on dimensional accuracy. After the mold is assembled, the inspector will inspect according to the mold inspection table. The main thing is to check whether the performance of the mold parts is good. Only in this way can the manufacturing quality of the mold be guaranteed.
3. Trial and repair
Although the mold design is carried out under the expected process conditions when the molding material and molding equipment are selected, people’s understanding is often imperfect. Therefore, after the mold processing is completed, a trial mold test must be carried out to see the molded part. How is the quality. After discovering that it is always the case, repair the model to eliminate errors.
There are many types of undesirable phenomena in plastic parts, and the reasons are very complicated. There are reasons for molds and process conditions, and the two are often intertwined. Before repairing the mold, according to the actual situation of the undesirable phenomenon of the plastic part, a detailed analysis and research should be carried out, and the remedy method should be proposed after finding the cause of the defect of the plastic part. Because the molding conditions are easy to change, the general approach is to change the molding conditions first, and only consider repairing the mold when the changing molding conditions cannot solve the problem.
Repair molds should be more cautious, and do not act rashly if you are not very sure. The reason is that once the mold conditions are changed, it cannot be remodeled and restored to the original state.
Whether the performance of the parts is good, only in this way can the manufacturing quality of the mold be
guaranteed.
Fourth, organize data and archive
After the mold has been tested, if it is not used temporarily, the mold release residue, dust, oil, etc. should be completely wiped off, coated with butter or other anti-rust oil or anti-rust agent, and kept in a storage place.
From the beginning of the design of the mold until the mold is successfully processed and passed the inspection, the technical data generated during this period, such as the task book, the part drawing, the technical manual, the mold assembly drawing, the mold part drawing, the base drawing, the mold design manual, and the inspection record Forms, trial and repair records, etc., are systematically sorted, bound, numbered and archived in accordance with regulations. This seems very troublesome, but it is very useful for repairing the mold in the future and designing a new mold.
