1. Draw the mold drawing
Before drawing the general assembly drawing of the mold, the process drawing should be drawn, and it must meet the requirements of the part drawing and process information. The size guaranteed by the next process should be marked with the words "process size" on the drawing. If no other mechanical processing is performed after forming except for repairing burrs, then the process drawing is exactly the same as the part drawing.
It is best to mark the part number, name, material, material shrinkage rate, drawing scale, etc. under the process drawing. Usually, the process drawing is drawn on the mold assembly drawing.
The ratio of 1:1 should be adopted as much as possible for drawing the general assembly drawing, starting from the cavity, and drawing the main view and other views at the same time.
The mold assembly drawing should include the following:
Mold forming part structure
Structural form of gating system and exhaust system.
Parting surface and parting method.
Outline structure and all connectors, positioning, and the location of guides.
Mark the height of the cavity (not mandatory, as needed) and the overall size of the mold.
Auxiliary tools (picking and unloading tools, calibration tools, etc.).
Number all parts in sequence and fill in the schedule.
Label the technical requirements and instructions for use.
The technical requirements of the mold assembly drawing:
For the performance requirements of certain systems in the mold. For example, the assembly requirements for the ejection system and the core-pulling structure of the slider.
Requirements for mold assembly process. For example, after the mold is assembled, the lamination gap of the joint surface of the parting surface should not be greater than 0.05mm. The parallelism requirements on the upper and lower sides of the mold should be specified, and the size determined by the assembly and the requirements for this size should be pointed out.
Mold use, assembly and disassembly methods.
Anti-oxidation treatment, mold number, lettering, marking, oil seal, storage and other requirements.
Requirements for mold testing and inspection.
The order of dismantling and drawing part drawings from the mold assembly drawing should be: first inside and then outside, first complex and then simple, first forming parts, and then structural parts.
Requirements are as follows:
graphic requirements
Be sure to draw to scale and allow for zooming in or out. Views are well chosen, projections are correct, and arrangements are well made. In order to make the processing patent number easy to understand and easy to assemble, the graphics should be consistent with the general assembly drawing as far as possible, and the graphics should be clear.
Dimensioning requires uniformity, concentration, order and completeness
The order of dimensioning is: first mark the main part size and draft angle, then mark the matching size, and then mark all the dimensions. On the drawings of non-main parts, first mark the matching dimensions, and then mark all the dimensions.
Surface roughness
Mark the most widely used roughness on the upper right corner of the drawing, such as marking "the rest 3.2." Other roughness symbols are marked on each surface of the part.
other content
For example, part name, mold drawing number, material grade, heat treatment and hardness requirements, surface treatment, graphic ratio, processing accuracy of free size, technical description, etc. must be filled in correctly.
2. Proofreading and drawing review
The relationship between the mold and its parts and the drawing of the plastic part
Whether the material, hardness, dimensional accuracy, and structure of the mold and mold parts meet the requirements of the plastic parts drawing.
Plastic parts
Whether the flow, shrinkage cavity, weld line, crack, and demoulding slope of the plastic material flow affect the performance, dimensional accuracy, and surface quality of plastic parts. Whether the pattern design is insufficient, whether the processing is simple, whether the shrinkage rate of the molding material is selected correctly.
Molding equipment
Whether the injection volume, injection pressure, and clamping force are sufficient, 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 is in correct contact with the socket.
Die structure
Whether the parting surface position and finishing precision meet the requirements, whether there will be overflow, and whether the plastic part can be guaranteed to stay on the side of the mold with ejector device after mold opening.
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 it will cause scratches to the molded parts.
Mold temperature regulation. The power and quantity of the heater; whether the position, size and quantity of the flow line of the cooling medium are appropriate.
The method of dealing with undercuts made of plastic parts, whether the mechanism for removing undercuts is appropriate, for example, whether the slider and push rod in the inclined guide column core-pulling mechanism interfere with each other.
Whether the position and size of pouring and exhaust system are appropriate.
Design drawings
Whether the placement of each mold part on the assembly drawing is appropriate, whether it is clearly expressed, and whether there are any omissions;
Part number, name, production quantity, in-house or outsourced part on the part drawing, standard or non-standard part, part matching processing accuracy, correction processing and allowance at high-precision dimensions of molded plastic parts, mold parts Whether the material, heat treatment, surface treatment, and surface finishing degree are marked and clearly described.
The main parts of the parts, the working dimensions and matching dimensions of the formed parts. Dimension figures should be correct and do not make conversions by the producer.
Check the view positions of all parts drawings and general assembly drawings, whether the projection is correct, whether the drawing method conforms to the national drawing standard, and whether there are any missing dimensions.
Check processing performance
Whether the geometric structure, view drawing method, dimension mark, etc. of all parts are conducive to processing
Main working dimensions of the recalculation aid
In principle, professional proofreading is carried out according to the designer's self-proofing project; however, it should focus on structural principles, process performance and operational safety. When making a 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. After scanning, self-check and sign.
Submit the drawn base map to the designer for proofreading and signing. It is a customary practice for the relevant technical personnel of the tool manufacturing unit to review, countersign, and check the manufacturing process before sending it to the public.
Writing Manufacturing Process Cards
The technical staff of the tool manufacturing unit writes the manufacturing process card and prepares it 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 assembly is completed, 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. Mold trial and mold repair
Although the mold design is carried out under the expected process conditions when the molding materials and molding equipment are selected, people's understanding is often incomplete. Therefore, it is necessary to conduct a mold trial test after the mold processing is completed to see the molded parts. How is the quality. It is always found later, and the model is repaired to eliminate errors.
There are many types of defects in plastic parts, and the reasons are also very complicated. There are reasons for molds and process conditions, and the two are often combined.
Before repairing the mold, it should be carefully analyzed and studied according to the actual situation of the defective phenomenon of the plastic part, and the remedy method should be proposed after finding out the cause of the defect of the plastic part. Because the molding conditions are easy to change, the general practice is to change the molding conditions first, and only consider repairing the mold when changing the molding conditions cannot solve the problem.
You should be more cautious when repairing molds, and you should not act rashly if you are not very sure. The reason is that once the mold conditions are changed, major modifications and restoration to the original state cannot be made.
Whether the performance of the parts is good or not, only in this way can the manufacturing quality of the mold be judged.
4. Organize data for archiving
After the mold is tested, if it is not used for the time being, it should completely wipe off the demoulding residue, dust, oil, etc., apply butter or other anti-rust oil or anti-rust agent, and store it in a storage place.
From designing the mold to successfully processing the mold and passing the inspection, the technical information generated during this period, such as task book, part drawing, technical specification, mold assembly drawing, mold part drawing, base drawing, mold design specification, inspection record Forms, mold trial and repair records, etc., shall be systematically organized, bound, numbered and archived according to regulations. It seems troublesome to do so, but it is very useful for repairing the mold and designing a new mold in the future.
