It is required to be drawn in accordance with national drawing standards, but it is also required to combine factory standards and factory customary drawing methods that are not specified by country. Before drawing mold assembly drawing, process drawing should be drawn and must comply with requirements of part drawing and process data. Dimensions guaranteed by next process should be marked with words "process dimensions" on drawing. If no other mechanical processing is performed after molding except for burr repair, then process drawing will be exactly same as part drawing.

 

It is best to mark the part number, name, material, material shrinkage, drawing scale, etc. below process diagram. Usually process is drawn on mold assembly drawing.

When drawing general assembly drawing, try to use a 1:1 ratio, start with cavity, draw main view and other views at the same time.
(1) Mold assembly drawing should include following contents
1) Mold forming part structure
2) Structural form of pouring system and exhaust system.
3) Parting surface and parting pick-up method.
4) Appearance structure and all connecting parts, positioning, and position of guide parts.
5) Mark cavity height dimension (not required, as needed) and the overall size of mold.
6) Auxiliary tools (piece removal and mold removal tools, correction tools, etc.).
7) Number all parts in order and fill in detailed list.
8) Mark technical requirements and instructions for use.
(2) Technical requirements of mold assembly drawing
1) Performance requirements for certain systems of mold. For example, there are assembly requirements for ejection systems and slider core-pulling structures.
2) Requirements for mold assembly process. For example, after mold is assembled, fitting gap of parting surface should be no greater than 0.05mm. Parallelism requirements on upper and lower sides of mold should be noted, size determined by assembly and requirements for this size should be pointed out.
3) Mold use, assembly and disassembly methods.
4) Anti-oxidation treatment, mold numbering, engraving, marking, oil sealing, storage and other requirements.
5) Requirements related to mold trial and inspection.

Order of disassembling and drawing parts drawings from mold assembly drawing should be: inside first then outside, complex first then simple, molded parts first, then structural parts.
(1) Graphical requirements
Be sure to draw to scale, allowing for enlargement or reduction. Views are well chosen, projected correctly, and laid out appropriately. In order to make processing patent number easy to understand and facilitate assembly, graphics should be consistent with assembly drawing as much as possible and graphics should be clear.
(2) Dimensions must be unified, centralized, orderly and complete
Order of marking dimensions is: first mark dimensions of main parts and draft angle, then mark matching dimensions, and mark all dimensions. On non-main parts drawings, mark matching dimensions first and then all dimensions.
(3) Surface roughness
Mark the most commonly used roughness in upper right corner of drawing, such as "Other 3.2." Other roughness symbols are marked on each surface of part.
(4) Other content
For example, part name, mold drawing number, material grade, heat treatment and hardness requirements, surface treatment, graphic proportions, free-size processing accuracy, technical description, etc. must be filled in correctly.

Self-proof content:
(1) Relationship between mold and its parts and plastic part drawings
Whether material, hardness, dimensional accuracy, structure, etc. of mold and mold parts meet requirements of plastic part drawings.
(2) Plastic parts
Whether flow of plastic material flow, shrinkage holes, weld marks, cracks, demoulding slope, etc. affect performance, dimensional accuracy, surface quality and other requirements of plastic parts. Is there any deficiencies in pattern design, is processing simple, and is shrinkage rate of molding material selected correctly?
(3) Molding equipment
Whether injection volume, injection pressure, and clamping force are sufficient, whether there are any problems with installation of mold, core of plastic parts, and demoulding, whether nozzle of injection machine and mouth sleeve are in correct contact.
(4) Mold structure
1) Whether parting surface position and finishing accuracy meet requirements, will overflow occur, and whether plastic parts can be ensured to remain on the side of mold with ejection device after mold is opened.
2) Whether demoulding method is correct, whether size, position and quantity of extension rod and push tube are appropriate, whether push plate will be stuck by core, and whether it will cause scratches on molded parts.
3) Mold temperature adjustment. Power and quantity of heater; whether location, size and quantity of flow line of cooling medium are appropriate.
4) How to deal with undercuts in plastic parts, and whether mechanism for removing undercuts is appropriate, such as whether slider and push rod in inclined guide column core-pulling mechanism interfere with each other.
5) Whether location and size of pouring and exhaust systems are appropriate.

 

(5) Design drawings
1) Whether placement of each mold part on assembly drawing is appropriate, whether representation is clear, and whether there are any omissions
2) Part number and name on parts drawing, production quantity, whether part is made in-house or outsourced, whether it is a standard part or a non-standard part, processing accuracy of parts, correction processing and allowance of high-precision dimensions of molded plastic parts, and whether materials, heat treatment, surface treatment, surface finishing of mold parts are clearly marked and described. 
3) Working dimensions and matching dimensions of main parts, molded parts. Size figures should be correct and do not require manufacturer conversions.
4) Check view positions of all parts drawings and assembly drawings, whether projection is correct, whether drawing method complies with national drawing standards, and whether there are any missing dimensions.
(6) Check processing performance
Whether geometric structure, view drawing method, size labeling, etc. of all parts are conducive to processing
(7) Main working dimensions of recalculation auxiliary tools
1) In principle, professional proofreading is carried out according to designer's self-checking project; but it must focus on structural principles, process performance and operational safety.
When drawing, you must first digest graphics, draw them according to national standards, fill in all dimensions and technical requirements. After tracing, self-correct and sign.
2) Submit traced base drawing to designer for proofreading and signature. Common practice is for relevant technical personnel of tool manufacturing unit to review, countersign, and check manufacturing process before sending it to the public.
(8) Compile manufacturing process cards
Technical personnel of tool manufacturing unit prepare manufacturing process card and prepare it for processing and manufacturing.
In manufacturing process of mold parts, inspection should be strengthened and focus of inspection should be on dimensional accuracy. After mold assembly is completed, inspector will inspect it according to mold inspection form. Main thing is to check whether performance of mold parts is good. Only in this way can the manufacturing quality of mold be guaranteed.

Although mold design is carried out under expected process conditions when selecting molding materials and molding equipment, people's understanding is often imperfect. Therefore, it is necessary to conduct a trial mold test after mold processing is completed to see quality of formed parts. After discovery is made, mold will be repaired to eliminate error.
There are many types of defects in plastic parts, and reasons are also very complicated. There are reasons for molds and process conditions, and the two are often intertwined. Before repairing mold, a detailed analysis and study should be conducted based on actual situation of adverse phenomena in plastic parts, causes of defects in plastic parts should be found out and remedies should be proposed. Because molding conditions are easy to change, general approach is to change molding conditions first. When changing molding conditions cannot solve problem, repair mold is considered.
You should be more cautious when repairing molds, and do not act rashly if you are not very sure. Reason is that once mold conditions are changed, major modifications and restoration to original state cannot be made.
Whether performance of parts is good or not, only in this way can manufacturing quality of mold be judged.

 

After mold is tested, if it is not used temporarily, demoulding 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 designing mold to successfully processing mold and passing inspection, technical data generated during this period, such as mission sheets, part drawings, technical specifications, mold assembly drawings, mold parts drawings, base drawings, mold design instructions, and inspection records, mold trial and repair records, etc., shall be systematically organized, bound, numbered and filed according to regulations. This may seem troublesome, but it will be very useful for repairing mold and designing new molds in the future.