Time：2019-06-22| Author：Admin
First, accept the task book
The task book for forming plastic parts is usually proposed by the part designer, and its contents are as follows:
1. The formal drawings of the finished parts that have been reviewed, and indicate the grades and transparency of the plastics used.
2. Plastic parts specifications or technical requirements.
3. Production output.
4. Samples of plastic parts.
1. Digest the plastic parts drawing, understand the use of the parts, analyze the technical requirements of the plastic parts, dimensional accuracy and other technical requirements.
2. Digest the process data, analyze whether the requirements of the molding method, equipment model, material specification, mold structure type, etc. proposed in the process task book are appropriate and can be implemented.
3. Determine the forming method – using direct pressure, casting or injection molding.
4, choose molding equipment
5. Specific structural plan
(1) Determine the mold type
Such as pressing die (open, semi-closed, closed), casting die, injection mold and so on.
(2) Determine the main structure of the mold type
Third, there are many factors affecting the mold structure and individual system of the mold, which is very complicated:
1. Cavity arrangement. The number of cavities and their arrangement are determined according to the geometrical features of the plastic parts, the dimensional accuracy requirements, the batch size, the difficulty in mold manufacturing, and the cost of the mold.
2. Determine the parting surface. The position of the parting surface is conducive to mold processing, exhaust, demoulding and forming operations, surface quality of plastic parts, etc.
3. Determine the gating system (the shape, position, and size of the main runner, split runner, and gate) and the exhaust system (how to vent, vent position, size).
4. Select the ejector method (jack, top tube, push plate, combined ejector) to determine the undercut treatment method and core pulling method.
5. Determine the shape, position, and mounting location of the heating element for cooling, heating, and heating and cooling grooves.
6. According to the mold material, strength calculation or empirical data, determine the thickness and shape of the mold parts, the shape and structure, and the position of all connections, positioning and guides.
7. Determine the main molded part, the structural form of the structural part.
8. Calculate the working dimensions of the molded part by considering the strength of each part of the mold.
Fourth, draw the mold map
It is required to draw according to the national drawing standard, but it also requires the combination of factory standards and factory customary methods not specified by the state.
It is best to mark the part number, name, material, material shrinkage rate, drawing ratio, etc. under the process diagram. Usually the process picture is on the mold assembly drawing.
Draw the final assembly drawing as much as possible with a 1:1 ratio, starting with the cavity and drawing the main view at the same time as the other views.
Mold forming part structure
2. The structure of the gating system and exhaust system.
3. Parting surface and parting mode.
4. Outline structure and position of all connectors, positioning and guides.
5. Mark the cavity height dimension (not required, as needed) and the overall dimensions of the mold.
6. Auxiliary tools (remove unloading tools, calibration tools, etc.).
7. Program all the part numbers in order and fill out the schedule.
8. Label technical requirements and instructions for use.
Sixth, the technical requirements of the mold assembly drawing
1. Performance requirements for certain systems of the mold. For example, the assembly requirements for the ejector system and the slider core structure.
2. Requirements for the mold assembly process. For example, the fitting gap of the mating surface of the parting surface after the mold is assembled should be no more than 0.05 mm, the parallelism of the upper and lower parts of the mold, and the size determined by the assembly and the requirement for the size are indicated.
3. Mold use, assembly and disassembly methods.
4. Anti-oxidation treatment, mold number, lettering, marking, oil seal, storage and other requirements.
5. Requirements for test and inspection.
Seven, draw all parts map
The order of drawing the parts drawing from the mold assembly drawing should be: first inside and then outside, first complicated and then simple, first forming parts, then structural parts.
1. Graphics requirements: Be sure to draw in proportions, allowing you to zoom in or out. The view selection is reasonable, the projection is correct, and the layout is proper. 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 final assembly drawing, and the graphics should be clear.
2. Dimensioning requirements are uniform, centralized, orderly, and complete. The order of dimensioning is: first mark the main part size and the draft angle, then mark the fit size, and then mark the full size. Mark the fit size on the non-main part drawing and mark the full size.
3. Surface roughness. Mark the roughness of the most applied type in the upper right corner of the drawing, as marked "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 scale, free-size machining accuracy, technical description, etc. must be correctly filled out.
Eight, proofreading, reviewing, drawing, sending sun
(1) The content of self-proofing is:
1. The relationship between molds and their parts and plastic parts drawings
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
3. Forming equipment
4. Mold structure
1). Whether the position of the parting surface and the precision of the finishing meet the requirements, will there be any flashing, and whether the plastic part can be left on the side of the mold with the ejector device after the mold is opened.
2). Is the demoulding method correct? Is the size, position and quantity of the promotion rod and the push tube appropriate? Will the push plate be caught by the core and will not cause the molded part to be scratched.
3). Mold temperature adjustment. The power and quantity of the heater; whether the flow line position, size and quantity of the cooling medium are suitable.
4). The method of processing the undercut of the plastic part, whether the mechanism for removing the concave side is appropriate, for example, whether the slider and the push rod in the core pulling mechanism of the inclined guide column interfere with each other.
5). The position of the pouring and exhaust system is appropriate.
5. Design drawings
1). Is the placement of each mold part on the assembly drawing appropriate? Is it clear whether there is any omission?
2). The part number, name, number of production, part internal or outsourced on the parts drawing, whether it is standard or non-standard parts, the precision of the part processing, the correction processing and the margin of the high-precision size of the molded plastic parts Whether the material of the mold part, heat treatment, surface treatment, surface finishing degree is marked, and the description is clear.
3). The main parts of the parts, the working dimensions of the molded parts and the matching dimensions. The size figures should be correct and should not be converted by the manufacturer.
4). Check the view position of all parts drawing and assembly drawing, whether the projection is correct, whether the drawing conforms to the national standard of drawing, and whether there is any missing size.
7. The main working size of the recalculation aid
(2) Professional proofreading is carried out in principle according to the designer's self-calibration project; however, it should focus on structural principles, process performance and operational safety.
(3). Submit the prepared base map to the designer for proofreading. The customary practice is to review the technical personnel of the tool manufacturing unit, sign and check the manufacturing process, and then send the sun.
(4). Writing manufacturing process cards
Nine, try and repair
Although the mold design is carried out under the expected process conditions when selecting molding materials and molding equipment, people's understanding is often imperfect. Therefore, after the mold processing is completed, the mold test must be carried out to see the molded parts. How is the quality? It is found that always afterwards, the erroneous revision is performed.
X. Organize data for archiving
After the mold has been tested, if it is not used for a while, it should be completely wiped off the mold residue, dust, oil, etc., coated with butter or other anti-rust oil or rust inhibitor, and kept in a storage place.
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