Machining drawing is the design drawing of mold design.
Design steps
1. Analyze the feasibility of the designed die products. Take the computer case as an example. Firstly, the product drawings of each component are analyzed by design software, which is called a set of drawings in our work to ensure the correctness of the product drawings before mold design. On the other hand, we can be familiar with the importance of each component in the whole case to determine the key dimensions, which is very beneficial in mold design. The specific method of painting is not introduced in detail here.
2. The work to be done after product analysis, what kind of die structure is used to analyze the product, arrange the products, determine the stamping content of each process, and use the design software to expand the products. When a product is unfolded, it is usually unfolded from the subsequent projects. For example, a product needs five processes.
After stamping is completed, start from the product drawings to the fourth project, the third project, the second project and the first project, and then copy a graphic before the previous project is launched, that is, complete the product development work of the fifth project, and then carry out the detailed work. Note that this step is very important and needs special care.
If this step is completed well, it will save a lot of time when drawing the mold drawing. After the stamping content of each project is determined, including in the forming die, the inner and outer lines of the product material thickness are reserved to determine the size of the punch. The method of product development is not explained here, but will be introduced in detail in the product development method.
3, material preparation, according to the product development diagram, determine the template size in the drawing, including all fixed plates, discharging plates, convex and concave dies, inserts, etc. Pay attention to preparing materials directly in the product development drawing, which is of great benefit to drawing the mold drawing. I have seen many mold designer directly calculate product development drawings to prepare materials.
This method is too inefficient. Template specifications and dimensions are directly drawn on the drawings and expressed in the form of assembly drawings. On the one hand, it can complete the material preparation, on the other hand, it can save a lot of work in the work of various parts of the mold, because only positioning, pins, guide pillars and screw holes need to be added in the material preparation drawing.
4. After the material preparation is completed, you can completely enter the drawing of the die drawing, and make another copy in the material preparation drawing to draw all the parts, such as screw holes, guide post holes, positioning holes, etc. In the stamping die, the forming gap between the upper and lower dies must not be forgotten, so the die drawing of a product is almost 80% after these works are completed. In addition, in the process of drawing the die drawing,
Every process, such as scribing and wire cutting, has a complete layer, which is of great benefit to wire cutting and drawing management, such as color discrimination. Sizing is also a very important job, and it is also the most troublesome job, because it wastes too much time.
5. After the above drawings are completed, it is actually impossible to draw. It is necessary to proofread the mold drawings, assemble all the accessories, make different layers for each different template, analyze the mold assembly with the same benchmark, such as the guide post hole, and put the product development drawing of each process into the assembly drawing to ensure that the hole position of each template is consistent and the gap between the upper and lower molds at the bend is correct.
Extended data
It is best to indicate the part number, name, material, material shrinkage, stretching ratio, etc. Under the flow chart. Usually, the process is drawn on the mold assembly drawing.
First, draw the assembly structure diagram
When drawing the assembly drawing, the ratio of 1: 1 should be adopted as far as possible, starting from the cavity, and drawing the front view and other views at the same time.
The mold assembly drawing shall include the following contents:
(1) the structure of mould forming parts
② Structure of gating system and exhaust system.
③ Parting surface and method.
(4) The external structure and the positions of all connectors, positioning and guiding.
⑤ Mark the cavity height size (not required, as required) and the overall size of the mold.
6. Auxiliary tools (mold taking, demoulding tools, calibration tools, etc.). ).
⑦ Make up the serial numbers of all parts in sequence and fill in the detailed list.
⑧ Mark the technical requirements and instructions for use.
B, mold assembly drawing technical requirements:
① Performance requirements of some mold systems. For example, the assembly requirements of the ejection system and the slider core-pulling structure.
(2) mold assembly process requirements. For example, the joint clearance of the parting surface should not be greater than the parallelism requirement of the upper and lower surfaces of the 0.05mm mold after clamping, and the size determined by assembly and the requirements for this size are pointed out.
③ Method of using and disassembling the mold.
④ Anti-oxidation treatment, module number, lettering, marking, oil seal, storage and other requirements.
⑤ Mold test and inspection requirements.
C, draw all parts.
The order of drawing parts from the die assembly drawing should be: first inside and then outside, first complex and then simple, first forming parts, then structural parts.
① Graphic requirements: it must be drawn in proportion, and enlargement or reduction is allowed. Reasonable scene selection, correct projection and proper layout. In order to make the processing patent number easy to understand and assemble, the figure should be as consistent and clear as possible with the general assembly drawing.
(2) Dimensions should be unified, centralized, orderly and complete. The order of dimensioning is: first dimension the main part size and draft angle, then dimension the matching size, and then dimension all dimensions. On the drawing of non-major parts, the matching dimensions are marked first, and then all dimensions are marked.
③ Surface roughness. Mark the most widely used roughness in 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, mold drawing number, material grade, heat treatment and hardness requirements, surface treatment, graphic proportion, free dimension machining accuracy, technical description, etc. , should be filled in correctly.
D, proofreading, drawing examination, drawing tracing and drying.
The content of self-calibration is:
(1) The relationship between the mold and its parts and the drawings of plastic parts, and whether the materials, hardness, dimensional accuracy and structure of the mold and its parts meet the requirements of the drawings of plastic parts.
② Plastic parts.
Whether the flow, shrinkage cavity, weld mark, crack and demoulding inclination of plastic material flow affect the requirements of plastic parts in terms of performance, dimensional accuracy and surface quality. Whether the pattern design is insufficient, whether the processing is simple, and whether the shrinkage of the molding material is selected correctly.
③ Molding equipment.
Whether the injection quantity, injection pressure and clamping force are sufficient, whether there are problems in mold installation, plastic parts south core and demoulding, and whether the nozzle of the injection machine is in correct contact with the sleeve.
(4) Mold structure
A. Whether the position and finishing accuracy of parting surface meet the requirements, whether flash will appear, and whether the plastic parts can be kept on one side of the mold with ejector after mold opening.
B. Whether the demoulding method is correct, whether the size, position and quantity of extension rod and push tube are appropriate, whether the push plate will be stuck by the core, and whether the molded part has scratches.
C. mold temperature adjustment. Power and quantity of heaters; Whether the location, size and quantity of cooling medium streamline are appropriate.
D. How to deal with the side concave of plastic parts and whether the mechanism for removing the side concave is appropriate, such as whether the slider and push rod in the core-pulling mechanism of inclined guide pillar interfere with each other.
E. Whether the location and size of the pouring and exhaust system are appropriate.
F. Design drawings
G. Whether the placement parts of each mold part on the assembly drawing are appropriate and clearly expressed, and whether there are any omissions.
H Whether the part number and name, production quantity, self-made or purchased parts, standard parts or non-standard parts, matching machining accuracy of parts, correction machining and allowance at high-precision dimensions of molded plastic parts, materials of mold parts, heat treatment, surface treatment and surface finish are clearly marked and explained.
⑤ Working dimensions and fitting dimensions of main parts and molded parts. Size figures should be correct, don't let the manufacturer convert them.
⑥ Check the view position and projection of all parts drawings and assembly drawings, whether the drawing method meets the national drawing standards and whether there are any size omissions.
⑦ Check the machining performance: (Whether the geometric structure, view and size of all parts are favorable for machining)
⑧ Recalculate the main working dimensions of auxiliary tools.
Professional proofreading is conducted in principle according to the designer's self-calibration project; However, we should focus on the structural principle, process performance and operational safety. When drawing, you should first digest the drawing and fill in all the dimensions and technical requirements according to the national standard. Self-correcting signature after tracing. Traditionally, the sketch is proofread and signed by the designer, checked by the relevant technicians of the tool manufacturing unit, countersigned and checked for manufacturing manufacturability before being sent to Sun.
Pet-name ruby writing manufacturing process card.
The technical personnel of the tool manufacturing unit shall compile the manufacturing process card and make good preparations for processing and manufacturing. In the manufacturing process of mold parts, it is necessary to strengthen inspection, and the focus of inspection is dimensional accuracy. After the mold assembly is completed, the inspector will carry out inspection according to the mold inspection list, mainly to check whether the performance of the mold parts is good, and only in this way can the manufacturing quality of the mold be slandered.
(3) try to repair the mold.
Although the mold design is carried out under the expected technological conditions when selecting molding materials and molding equipment, people's understanding is often imperfect, so it is necessary to conduct a mold trial test after the mold processing is completed to see how the quality of the molded parts is. It's always discovered later, and repairing the mold eliminates mistakes.
There are many kinds of bad phenomena of plastic parts, and the reasons are also very complicated, including mold reasons and process conditions, which are often only together.
Before repairing the mold, we should make a detailed analysis and study according to the actual situation of the bad phenomenon of plastic parts, find out the causes of the defects of plastic parts, and then put forward the remedies. Because the molding conditions are easy to change, the general practice is to change the molding conditions first, and then consider mold repair when changing the molding conditions can't solve the problem.
Repair the mold more carefully, and you can't make a move without being quite sure. The reason is that once the mold conditions are changed, it cannot be rebuilt and restored.
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