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General process of injection mold design drawing

update:28-12-2019
abstract:

The process of designing and drawing plastic injection […]

The process of designing and drawing plastic injection molds varies from company to company, as shown in Table 1-7.
1.2.1 Organize and check customer information
(1) Detailed customer information
① 3D and 2D drawings or drawings of plastic parts.
② Plastic material and its shrinkage.
③ The appearance requirements and precision requirements of plastic parts.
④ Plastic assembly requirements and important assembly dimensions.
⑤ Requirements for injection molding conditions of plastic parts.
⑥ Plastic parts production batch, cycle, injection molding machine used and other special requirements.
After receiving the design task and the customer's plastic parts information, the person in charge of injection mold design should follow the mold design requirements, and truthfully and thoroughly send the data and requirements to each mold designer, and then the mold designer will sort out and digest the customer information.
(2) Organizing content
① If the customer data is in 3D form such as IGES, IDEAS, etc., convert it into UG or Pro / E solid form, and repair the broken surface.
Table 1-7 Mold design drawing process, person in charge at each stage, relevant documents
② If the data provided by the customer is a 2D drawing file or drawing, draw it into a UG or Pro / E drawing file as required.
(3) Inspection contents
① The orientation of the mold parting line and the position of the clamping line left on the plastic part must be approved by the customer if the appearance is affected.
② Are there any plastic parts that are easy to produce injection molding defects, such as shrinkage, burrs, scorching, etc. Whether the plastic parts have design defects that make the mold difficult or even impossible to process, such as undercuts and insufficient space? . If so, improvements must be made.
 ③ The lateral core pulling, oblique top position and clamping line, if the appearance is affected, the customer's consent must be obtained.
④ For the size of the plastic parts and the plastic parts (such as the front and rear covers), the tolerance of the die size must be determined.
⑤ Whether the mold release slope is marked in the plastic parts picture and whether the mold release slope is sufficient (special attention should be paid to the mold release slope of the transparent plastic parts, the etched surface and the insertion surface).
⑥ The plastic part has a font part to confirm the font form, content, position, and size (especially pay attention to the intaglio).
After the inspection, each designer will make the contents of the above inspection into a "plastic (product) inspection form" (DWG or PDF file) and summarize it to the design team leader. The design team leader will then send the email or fax to the customer Check, change, confirm.
(4) Modify the plastic parts and determine the plan
① Once the content of the inspection is confirmed by the customer or received by the customer, the modification of the plastic parts can be started according to the design and production requirements of the mold.
② Modifications include changing the demolding slope, modifying the buckle structure, and rationalizing the wall thickness.
③ The modified plastic parts generally require the person in charge of the mold to be confirmed by the customer.
④ If necessary, the person in charge of the mold must convene a meeting of the design team leader and each designer to discuss the detailed plan for mold production.
1.2.2 Drawing of injection mold
1) The modified plastic parts are drawn by the designer in 3D mold drawings.
2) Once the design task is issued, the person in charge of the mold will instruct the relevant engineers to formulate a "mold production plan" according to customer requirements, and determine and notify each designer in the shortest time.
3) "Mold Production Plan" is the necessary data basis for mold design and manufacturing. Designers need to pay attention to their version updates at any time and respond in time.
4) At the beginning of construction, the mold design team leader needs to fill in the "Mold Design Plan" according to the specific situation, and then report it to the person in charge of the mold. designer.
5) "Mold design plan" is the time basis for mold design and production, and is an important document to ensure the progress of mold making. Once the design plan is issued, each designer must complete the drawing within the time limit specified in the plan, and no extension can be made without special circumstances.
6) Each designer should pay attention to the update of plastic parts at any time to ensure that the design mold products are the latest version. If any problems are found, they should be reported to the team leader or the mold manager in time.
7) If the customer has special technical requirements for the mold, it shall be designed according to its requirements, and the design content shall be confirmed by the customer before it can be officially produced.
8) The mold design department should formulate the "Internal Technical Specifications of the Mold Design Center" based on the company's design experience over the years, as a unified technical basis for the design and production of each designer. Each design content must be detailed, accurate and meet the requirements of the specification.
9) After the mold drawing is completed, each designer will copy the document to the specified document and notify the person in charge of the mold department to check and proofread.
10) After the mold owner completes the inspection, fill in the "Design Drawing Inspection Problem Record Form", and send a simple schematic diagram to the relevant designers.
11) The designer revises the design item by item according to the change opinions listed in the "Mold Design Drawing Inspection Problem Record Form". If there is any problem, please report it to the person in charge of the mold in time, sign it after the change, and send it to the person in charge of the mold for inspection and confirmation.
12) The person in charge of the mold checks again, and after confirming that it is correct, the customer or the product design engineer is notified that the mold design is complete and the mold starts manufacturing.
13) Notify relevant engineers to convert 3D mold drawings into 2D mold drawings and mark the dimensions. At the same time, submit the 3D drawings to CNC programming, and the purchased steel and standard parts to the purchasing department for procurement.
1.2.3 Design Standards for Injection Mold Drawings
1) Add the size of the plastic part to the shrinkage size, and then put it in the mold to become the cavity view after mirroring.
2) The mold reference must clearly indicate the mold reference and the plastic reference, and indicate the distance from the mold center.
3) Determine whether the size of the mold is appropriate according to the size of the plastic part. The general principles are as follows.
a. For two-plate mold, the value of A is generally 45 ~ 70mm, if there is a slider, it is about 100mm.
b. For three-plate mold, the value of A is generally 75 ~ 100mm, if there is a slider, it is about 150mm.
c. The size of plastic parts is <150mm × 150mm, C <30mm, then the value of B is generally 15 ~ 25mm, and the value of D is generally 25 ~ 50mm.
d. The size of the plastic part is ≥150mm × 150mm, then the value of B is generally 25 ~ 50mm.
The value of e.D is generally C + (20 ~ 40mm). E value: The moving template is generally larger than 2D; the fixed template is generally slightly smaller than 2D.
4) Confirm whether the plastic muscle contraction rate is correct. For some plastic parts, the shrinkage in all directions may not be the same. For plastic POM, the shrinkage selection method is: core type 2.2%, cavity 1.8%, parting surface and center distance 2.0%.
5) The reference angles of the mold base and the inner mold inserts must be marked and the directions should be the same, as shown in Figure 1-12.
6) Whether the demolding slope of the etched surface, transparent plastic part, and rubbing surface is reasonable. Generally, the etched surface is at least 1.5 °, and the transparent plastic part and the rubbing surface are at least 3 °.
7) The specification and size of the screw holes of the formwork ring must be clearly marked. For the formwork with a width of 450mm or more, the four sides of the A and B plates must be provided with screw holes.
8) The length of the screw, the depth of the screw hole, and the specifications must be marked, and the sequence number, such as S1, S2, etc.
9) The flow path of the cooling water holes must be clearly marked. The optimal distance between the cooling water holes is 50mm. The distance from the parting surface or plastic part is preferably 15-20mm. Pay attention to check whether the O-ring of the water hole interferes with the push rod, screw and inclined top.
10) The cooling water hole needs to be numbered, and the diameter and the thread of the water pipe joint must be marked, such as 1 # IN, 1 # OUT, 1 / 8PT, 1 / 4PT, etc.
11) Putters, push tubes and flat pushers generally need to be 2.0mm away from the edge of the cavity (such as RIB). The arrangement of pushers should be balanced as far as possible. 2. Push rod (such as Φ6.03mm × Φ3.02mm BOSS column boss should be ordered Φ6mm × Φ3mm), except for customer requirements.
12) It is necessary to mark the stroke of the slider and the inclined top, and confirm whether the stroke is reasonable.
13) The content, position, font size and depth (concave or convex) of the font on the plastic parts must be clearly marked in the insert drawing.
14) In the DWG drawing file of the mold, the same line type should be marked with the same color, such as:
a. The center line uses No. 1 red (sjgm.dwt center layer);
b. The dotted line uses light green No. 4 (unsee layer in sjgm.dwt);
c. The solid line uses white No. 7 (continuous layer in sjgm.dwt);
d. No. 5 green (sjgm.dwt pipe layer) is used uniformly for the cooling water channel;
e. Dimension lines use No. 3 blue uniformly, and text use No. 7 white (dim layer in sjgm.dwt);
f. The section line uniformly uses No. 8 gray (skg.dwt hatch layer);
g. The insert line uses No. 6 purple (lmag in sjgm.dwt).
15) Technical requirements in drawings
a. Technical requirements and general sequence:
a) Materials
b) quantity
c) heat treatment
d) plastic position identification
e) (at the non-glued position) chamfered edges
f) Description
b. General requirements
a) Technical requirements should be written in the lower left corner of the drawing and filled from top to bottom.
b) Technical requirements must have at least the three items a), b), and e) above, and items c), d), and f) may be optional as required. When the parts are modified with standard parts, the materials are marked with “STD” or “XXXXX (standard part code)”.
c. Examples of technical requirements:
skills requirement:
1. Material: S50C
2. Quantity: 1 piece
3.Edge chamfer: 1 × 45 °
skills requirement:
1. Material: NAK80
2. Quantity: 2 pieces
3. Desalination treatment, the depth of desalination layer is 0.15mm, 68 ~ 70HRC
4. Two-dot chain line indicates the glue plane, which is taken from the 3D model.
5.Edge chamfering of non-formed surface: 1 × 45 °
skills requirement:
1. Material: 01
2. Quantity: 2 pieces
3. Heat treatment: secondary tempering after quenching 52 ~ 56HRC
4.Edge chamfer: 1 × 45 °
skills requirement:
1. Material: 8407
2. Quantity: 2 pieces
3. Heat treatment: secondary tempering after quenching, 50 ~ 51HRC
4. The two-dot chain line indicates the glue plane, which is taken from the 3D model.
5.Edge chamfering of non-formed surface: 1 × 45 °
16) Layer management: Create different layers and place different types of part lines in different layers. For example, the dimension line is placed in the dim layer, the cooling water line is placed in the cool layer, the putter contour line is placed in the inject layer, the inner mold insert is placed in the insert layer, and the structural parts such as the mold frame are placed Within the mould layer etc.
1.2.4 Inspection of injection mold design drawings
Model: Name: Number of Cavities: Design: Time:
Plastic parts inspection:
Mouth demolding angle Mouth shrinkage Mouth pinch inspection Mouth interference inspection Mouth inspection Mouth wall thickness inspection
Inner mold insert inspection:
Orifice Screw, pusher, cooling water Orientation of insert Orifice Orifice Orthodontic vent
Mouth for measuring temperature of the mouth Mouth for avoiding the hole of the putter Mouth Product marking Mouth
Mouth is changed to No. 13 color on the surface. Mouth inclined hole for servo position Mouth screw hole Mouth wire cutting insert with R angle
Mouth Tie rod Mouth The part above the parting surface avoids the side by 0.5mm
The height of the carved insert surface is 0.2mm or more (concave)
Side core pulling mechanism:
Can wedges be used as standard parts? Slider spring length? Slider cooling
Orifice as standard Orifice with R angle at the top Orientation of the slider Orientation of the slider
Orientation of the top of the large wedge block Orifice
Standard size for insert positioning (according to CNC electrode size)
Mold structure:
口 Gate sleeve, positioning ring 口 Guide post exhaust slot 口 Up and down "T", "B" mark Port reset rod length
Port “IN”, “OUT” of cooling water Port of mold base Position of base of mold base Port of wedge to avoid emptying
Mouth support head Mouth plate guide bushing Mouth trash nail Mouth return spring
Mouth Top hole Mouth Limit post Mouth Mounting screw Mouth Clamp
Mouth Hanger hole Mouth Tension plate Mouth Pivot anti-rotation Mouth Avoid the cooling water connection to ɸ30mm
25mm high at the presser foot
Two-plate mold: locating pin between panel and A plate
Three-plate mold: mouth pull rod mouth cold material cavity mouth large draw rod mouth small draw rod mouth long guide post length calculation
Mouth length calculation Mouth Nylon plug with vent hole, hole chamfer R
other:
Mouth layer Mouth assembly part drawing Mouth folder name with barcode number
1.2.5 Follow-up of mold production
1) During CNC programming, if a mold design problem is found, the CNC person in charge should inform the mold 3D design person in charge of the problem in time, and the mold 3D design person in charge will arrange for the designer to modify the design and notify the 2D group and CNC programming group.
2) During mold production and processing, if there is a problem with the mold design, the mold manufacturing supervisor should promptly notify the mold design person in charge of the problem, and the mold design person in charge should notify the 3D design team leader in a timely manner, and the 3D design team leader in a timely manner. Arrange the designer to change the design and update the 3D design of the mold, and issue the mold modification information, and notify the 2D group and CNC programming group at the same time.
3) After the mold is tested, if a design defect is found, the responsible person in charge of the product engineering department shall promptly notify the mold design person in charge of the problem, and the mold design person in charge shall promptly notify the mold 3D design team leader and 3D design group The team leader then arranged for the designer to change the design and update the 3D in time, and issued the modification information, and notified the 2D group and the CNC programming group.
As mold production is in progress, all changes should be made to respond quickly to avoid delaying the mold period.
There are several cases of mold design changes

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