Do you know all the basic knowledge commonly used in mold design? Let’s review it together through the following 88 questions.
1. Commonly used plastic engineering materials and their shrinkage rates?
ABS: 0.5% (super unbreakable rubber)
PC: 0.5% (bulletproof glass glue)
PMMa: 0.5% (plexiglass)
PE: 2% (polyethylene)
PS: 0.5% (polystyrene)
PP: 2% (100% soft rubber)
PA: 2% (nylon)
PVC: 2% (polyvinyl chloride)
POM: 2% (steel steel)
ABS+PC: 0.4%
PC+ABS: 0.5%
Engineering materials: ABS PC PE POM PMMA PP PPO PS PET
2. How many systems are the molds divided into?
Pouring → Ejection → Cooling → Forming → Exhaust
3. What issues should be paid attention to during the mold design process?
(1) The wall thickness should be as uniform as possible, and the draft angle should be large enough.
(2) The transition part should be gradual and smooth, avoiding sharp corners.
(3) Gate. The flow channel should be as wide and short as possible, and the gate position should be set according to the shrinkage and condensation process. If necessary, a cold well should be added.
(4) The mold surface should be smooth and clean, with low roughness (preferably less than 0.8).
(5) The exhaust holes and slots must be sufficient to discharge air and gas in the melt in a timely manner.
(6) Except for PET, the wall thickness should not be too thin, generally not less than 1mm.
4. What are the common defects in plastic parts?
Lack of glue → Cloak → Bubbles → Shrinkage → Weld marks → Black spots → Stripes → Lifting → Layering → Peeling
5. Commonly used plastic mold steels?
45# S50c 718 738 718H
738H P20 2316 8407 H13
NAK80 NAK55 S136 S136H SKD61
6. What kind of material is used for high mirror polishing?
Commonly used high-hard heat-treated steels, such as: SKD61, 8407, S136
7. What structures does the mold base have?
Panel→A board→B board→square iron→guide post→ejector plate→ejector pin fixing plate→base plate
8. What are the basic forms of parting surfaces?
Straight→inclined→curved surface→vertical→curved surface
picture
9. How to hide each other in UG?
ctrl+B or ctrl+shift+B
10. What are the mold processing machinery and equipment?
Computer gong→Lathe→Milling machine→Grinder→Drilling machine
11. What is 2D and what is 3D?
The English word D is the prefix of Dimension. 2D refers to the two-dimensional plane, and 3D refers to the three-dimensional space. In the mold part, 2D usually refers to the plan view or CAD drawing, and 3D usually refers to the three-dimensional drawing.
12. What is the default precision of pro/e? What is the default precision of UG?
The default accuracy of pro/e is: 0.0012mm, and the default accuracy of UG is: 0.0254mm.
13. Among the top four global mold base manufacturers?
Germany: HASCO Japan: FUTABA (Double Leaves) United States: DME China: LKM (Longji)
14. What is the default font height of CAD?
The default CAD character height is: 2.5mm.
15. What is penetration and penetration?
The joint surface of the male and female molds that is parallel to the PL surface is called the penetration surface, and the joint surface of the male and female molds that is not parallel to the PL surface is called the insertion surface.
16. The relationship between strips and silk
Strips and wires are units of length. Strips are used in Taiwan, 1 strip = 0.01mm, and silk are used in Hong Kong, 1 wire = 0.01mm, so 1 strip = 1 wire.
17. What is the pillow position?
There are often notches on the edges of shell plastic parts, which are used to install various accessories. The pillow-shaped part formed here is called a pillow position.
18. What is a crater?
The shape of the glue-reduced part at the root of the BOOS column reflected on the mold after the volcanic eruption is called the mold crater.
19. What is the finger?
Ha refers to Mo Yan, a Hong Kong idiom.
20. What is the tiger’s mouth?
The tiger's mouth is also called: tube position, which is the part used to limit the position.
21. What is ranking?
The product layout on the mold is called ranking.
22. What is glue position?
The cavity of the product on the mold is called: glue level.
23. What is bone position?
The tendons on the product are called: bone positions.
24. What is column position?
The BOSS column on the product is called: column position.
25. What is virtual position?
The gap on the mold is called: virtual position.
26. What is deduction?
The hook used for connection on the product is called a buckle.
27. What are spark lines?
The lines left after EDM are called spark lines.
28. What PL side?
The PL surface, also known as: parting surface and pop-up surface, refers to the part where the front mold and the rear mold come into contact when the mold is closed.
29. What is a computer gong?
CNC milling machines and machining centers.
30. What is copperworking?
Electric sparks usually use easy-to-process copper materials as discharge electrodes, which are called copper workers, also called electrodes. Copper workers are generally divided into: rough workers, rough and young workers, and young workers. The young workers are also called fine workers.
31. What is the usual spark position?
During the discharge process, the discharge gap between the copper and steel materials is called the spark position. The rough sparks are generally 10 to 50, and the young sparks are generally 5 to 15.
32. What is the material level?
The thickness of plastic products is also called flesh thickness.
33. What is the original body left?
Relative to cutting inserts, original body retention refers to a whole piece of steel as a blank for processing, which is processed together during processing.
34. What are weld marks?
The line formed when two strands of plastic meet is called a weld mark.
35. What is a jet?
After the plastic enters the mold cavity from the plastic inlet, it forms a curved and folded snake-like flow mark called a jet.
36. What does LKM mean?
LKM refers to Longji mold base. Commonly used mold bases include: LKM, Fudeba, Mingli, Huansheng, Changhui and Desheng.
37. What does DME mean and what does HASCO mean?
DME and LKM are both standards for standard parts, DME is American-made, and HASCO is European-made.
38. What is undercut?
The parts of the product that cannot be directly demolded from the front and rear molds become undercuts.
39. What is foolproofing?
Fool-proofing is an idiom, which means to prevent a very simple mistake and to prevent being in a daze! For example: an insert has hangers of the same size on both the sky and the ground. During on-site assembly, it is very likely that the top and ground sides will be installed upside down, but he makes the hangers on one side of the insert. At this time, if the top and ground sides are installed upside down, It cannot be installed, and it is impossible to install it wrongly. This action to prevent errors caused by daze is called foolproofing.
40. What is a beer machine?
Beer machine is a local idiom, which is what we often call injection molding machine and molding machine.
41. What is silence?
The stop is the art line of the mouth, also known as the ugly line.
42. What is flying model?
Flying molds are matching molds or standard molds.
43. What is a light knife?
The action of CNC finishing is called light knife, which is to complete the machining in place based on rough cutting.
44. What is open frame?
The action of processing the position of the mold core on the mold base is called frame opening.
45. What is the word "Sha"?
Posting is to put the fonts on the film and then add fonts to the fonts.
46. What is opposition?
The method of opening the mold by inverting the front and rear mold material positions under normal circumstances is called reverse.
47. What is fuhe?
The mold ejection method of using small inserts to pop up parts with undercuts is called Fuhe.
48. What is eating the front mold?
When the mold is opened, the product remains in the front mold, which is called eating the front mold.
49. What is Dingbai?
When ejecting, the mold force required is large and the ejection pin is not strong enough, causing the product to be partially ejected. Viewed from the front of the product, there is an obvious white mark called ejection white, which is also called the ejection nozzle.
50. What is baking?
The traces left by the water entry point on the surface of the point made during diving are called baking marks.
51. What is a coder?
The clamp is a clamping tool, a pad with a triangular bevel and an opening slot.
52. What is overcutting?
Overcutting refers to excessive cutting, that is, when processing the workpiece, the parts that do not need to be processed are also processed. Overcutting is not good.
53. What is the school cup?
The front mold pops up and opens the inner position of the mold.
54. What is Yata?
Tapping, tapping thread is called thread.
55. When is it necessary to make a two-color mold?
When a product contains two different materials or the same material in different colors, a two-color mold is designed.
56. What is the factory’s mold design process?
The customer provides product drawings → analyzes the product → confirms the plastic variety → confirms the mold material → converts the engineering drawing → multiplies and shrinks to make a mirror image → complete the assembly drawing → order the mold base → order the mold core material → draft the mold → 3D parting → determine the flow channel / Gate method → refer to the layout diagram for structural design → dismantle the inserts → correct 3D → produce drawings of the project "including: mold core/inserts/mold base/parts" → make BOM list → proofread and review.
57. How many ways are there to remove the mold?
Smooth and forced ejaculation.
58. What are the methods of feeding glue?
Direct gluing → Overlap gluing → Side gluing → Circular gluing → Sheet gluing → Latent type → Point gluing → Horn type gluing → Fan-shaped gluing.
59. What are the forms of flow channels?
There are circular flow channels → semi-circular flow channels → T-shaped flow channels → regular hexagonal flow channels.
60. What are the standing manuals and books for mold designers?
Steel books, plastic books, mold standard parts books.
61. What is the function of spring?
Rebound when used externally.
62. Why does the mold need to be drafted?
Prevent the product from being strained when it is removed from the mold.
63. What is the function of screws and how to determine the matching length?
It mainly plays the role of tightening and fixing. The matching length is generally 1.5 to 2 times the diameter of the screw.
64. What is the general slope of the slider and the slope of the inclined guide column?
The slope of the slider is generally 20 degrees, and the slope of the inclined guide column is generally 18 degrees.
65. What is the function of cold well?
The function of the cold material well is to store the small portion of relatively low-temperature plastic material that enters the mold first.
66. What is the function of positioning ring?
The function of the positioning ring is to ensure that the correct relative position between the mold and the injection machine is maintained.
67. The relative position of coordination?
Fits are mainly divided into three categories: clearance fit, transition fit, and interference fit.
68. What is the function of inserts?
It facilitates processing, prevents carbon deposits, facilitates polishing, saves materials, helps exhaust, facilitates replacement, and reduces the size of the processing machine.
69. What are the indicators of hardness?
Hardness indicates the ability of a material to resist hard objects being pressed into its surface. Commonly used hardness indicators include Brinell hardness, Rockwell hardness and Vickers hardness.
70. Can curved surfaces be drafted? Can the group be drafted? Can the quilt be replaced?
Curved surfaces cannot be drafted, group surfaces can be drafted, and quilt groups can be replaced.
71. What is the difference between the first angle method and the third angle method?
① Any drawing method that places an object in the first quadrant and projects the view in the relationship of (viewpoint) (observer) → (object) → (projection surface) is called the first angle method, also known as the first quadrant method. .
②Any drawing method that places an object in the third quadrant and projects the view in the relationship of (viewpoint) (observer) → (projection plane) → (object) is called the third angle method, also known as the third quadrant method.
Note: The difference between the first angle drawing method and the third angle drawing method is the article placement of the view.
How to draw the first corner: put the left view on the right, the right view on the left, the top view on the bottom, and so on...
Third angle drawing method: put the left view on the left, the right view on the right, the top view on top, and so on...
72. What are the ways to transport water?
Commonly used types for water transportation include: straight-through type, wrap-around type, water tower type, and spiral type.
73. What are the basic principles of three views?
The basic principles of three views are: length is aligned, height is equal, and width is equal.
74. What are the categories of injection machines?
According to the appearance, they are divided into: vertical and horizontal; according to the injection volume, they are divided into: ultra-small injection molding machine, small injection molding machine, medium-sized injection molding machine, large injection molding machine, and super-large injection molding machine; according to the mold clamping force, they are divided into: several tons to several thousand tons.
75. What is the relationship between clamping force and mold supporting force?
The clamping force of the injection molding machine must be greater than the mold opening force, otherwise the mold will be opened by the pressure within the mold.
76. What are the positioning methods of male and female molds?
There are two types of positioning methods for the front and rear molds: one is template positioning, and the other is mold core positioning.
77. What is the appropriate wall thickness for commonly used plastics?
The suitable wall thickness of ABS is: 1.8~3mm, the suitable wall thickness of PC is: 2~3.5mm, the suitable wall thickness of POM is: 1.5~2.5mm, the suitable wall thickness of NoryL is: 2~3.5mm.
78. What is overflow value?
The overflow value refers to the gap under which the plastic product will overflow. The overflow value of ABS is 0.04mm, the overflow value of PC is 0.06mm, the overflow value of PA is 0.015mm, and the suitable wall thickness of POM is 0.04mm, the overflow value of PBT+15%GR is 0.03mm, the overflow value of PBT+30% is 002mm, the overflow value of PMMA is 0.065mm, the overflow value of PVC is 0.07mm, the overflow value of AS The overflow value of PS is 0.05mm, the overflow value of PP is 0.03mm, and the overflow value of PE is 0.02mm.
79. What is the size of a standard picture frame?
Commonly used picture frames are: A0, A1, A2, A3, A4. The size of the picture frame of A0 is: 1189mx841m, the size of the picture frame of A1 is: 841mx594mm, the size of the picture frame of A2 is: 594mmx420mm, the size of the picture frame of A3 The size of the frame is: 420mmx297mm, and the size of the A4 picture frame is: 297mmx210mm.
80. Planning of mold size?
Each company has different standards for planning mold sizes, but the common standards are as follows: molds of 15 to 30 series mold bases are classified as small molds, molds of 30 to 50 series mold bases are classified as medium molds, and molds of 50 to 50 series mold bases are classified as medium molds. The mold of the mold base is listed as a large mold.
81. What is elastic deformation? What is plastic deformation?
An object deforms under the action of an external force. When the external force disappears, the object can return to the deformation before deformation, which is called elastic deformation. When the external force disappears, the object cannot return to the deformation before deformation, which is called plastic deformation.
82. What materials are commonly used for mold bases?
Mold bases are often made of trump steel (called in Hong Kong), which is medium carbon steel and 45 steel.
83. What is the difference between CAD drawing working model space and layout space?
Model space is the space for graphic entities, and layout space is the space for drawing layout.
84. What is the function of water transport?
The function of water transport: control the temperature of the mold core.
85. What is a mold?
In industrial production, various presses and special tools mounted on the press are used to make parts or products of the required shape from metal or non-metallic materials through pressure. Such special tools are collectively called molds.
86. Classification of molds?
Molds can generally be divided into plastic molds and non-plastic molds. Non-plastic molds include: casting molds, forging molds, stamping molds, die-casting molds, and plastic molds. According to the different production processes and products, they are divided into: injection molding mold, blow mold, compression molding mold, transfer molding mold, extrusion molding mold, thermoforming mold, and rotation molding mold. According to the different types of pouring systems, molds can be divided into three categories: large nozzle molds, fine
Nozzle mold, hot runner mold.
87. What is a pouring system?
The plastic flow channel from the injection machine nozzle to the mold cavity is called the gating system. The gating system includes: main channel, branch channel, gate and cold well.
88. What is reverse engineering?
Reverse engineering uses a high-speed three-dimensional laser scanner to scan existing samples or models accurately and at high speed to obtain their three-dimensional contour data, then performs curve reconstruction with reverse software, and conducts online accuracy analysis and evaluation of the reconstructed surface. After constructing the effect and finally generating IGES or STL data, rapid prototyping or CNC machining can be carried out in one step.
