80 Casting mold questions and answers

1. Common engineering materials and shrinkage rate?
ABS: 0.5% (super broken glue)

Pc: 0.5% (bulletproof glass glue)
PMMa: 0.5%: (Plexiglas)
Pe: 2% polyethylene
PS: 0.5% (polystyrene)
Pp: 2% (100% soft rubber)
PA: 2% (nylon)
PVC: 2% (polyvinyl chloride)
POM: 2% (Sai ​​Steel)
ABS+PC: 0.4%
PC+ABS: 0.5%
Engineering materials: ABS PC PE POM PMMA PP PPO PS PET

2. What are the major systems for the mold?
Pouring → ejection → cooling → forming → exhaust

3. What problems should I pay 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 gradually and smoothly transitioned to prevent sharp corners.
(3) Gate. The flow path should be as wide and thick as possible, and the gate position should be set according to the shrinkage condensation process. If necessary, a cold well should be added.
(4) The surface of the mold should be smooth and the roughness is low (preferably 0.8)
(5) The venting holes, the slots must be sufficient to expel the air and the gases in the melt.
(6) Except for PET, the wall thickness should not be too thin, generally not less than 1mm.

4. What are the common occurrences of plastic parts?
Lack of glue → cloak → bubble → shrinkage → weld mark → black point → stripe → lift up → layering → peeling

5. Commonly used plastic mold steel?
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 steel, such as: SKD61, 8407, S136

7. What are the structures of the formwork?
Panel → A plate → B plate → square iron → guide column → thimble plate → thimble fixed plate → bottom plate

8. What are the basic forms of the parting surface?
Straight → Tilt → Surface → Vertical → Arc Surface

9, how to hide each other in UG?
ctrL+B or ctrL+shift+B

10. What are the mold processing machinery and equipment?
Computer 锣→Lathe→Milling Machine→Grinding Machine→Drilling Machine

11, what is 2D, what is 3D?
The English of D is: the head of Dimension (dimension, dimension), 2D refers to the two-dimensional plane, 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 perspective view.

12. What is the default accuracy of pro/e? What is the default accuracy of UG?
The default precision of pro/e is: 0.0012MM, and the default precision of UG is: 0.0254MM.

13. What are the top four manufacturers of global formwork production?
Germany: HASCO Japan: FUTABA (double leaf) USA: DME China: LKM (龙记)

14. What is the default word height for CAD?
The default font height for CAD is: 2.5MM.

15. What is the wearing and what is the insertion?
The mating surface of the male and female molds parallel to the PL surface is called the collision surface, and the surface of the male and female molds that are not parallel to the PL surface is called the insertion surface.

16, the relationship between the strip and the wire
Both the strip and the silk are length units, the strip is Taiwanese, 1 = 0.01MM, the silk is Hong Kong, 1 silk = 0.01MM, so 1 = 1 silk.

17. What is the pillow position?
The edges of the outer shell plastic parts are often notched and used to install various types of accessories. The part of the pillow formed here is called the pillow position.

18. What is the crater?
The shape of the BOOS column root rubber reduction is reflected in the shape of the mold after the volcanic eruption is called the mold crater.

19. What is your finger?
He refers to the model, Hong Kong idioms.

20. What is the tiger’s mouth?
The tiger’s mouth is also called: the tube position, which is the part used for the limit.

21. What is ranking?
The product layout on the mold is called the ranking.

22. What is the glue position?
The cavity of the product on the mold is called: the glue position.

23, what is the bone position?
The tendons on the product are called: bone position

24. What is a column?
The column of BOSS on the product is called: column position.

25. What is a virtual position?
The gap on the mold is called: virtual position.

26. What is the deduction?
The hook used to connect the product is called: buckle.

27. What is the fire pattern?
The pattern left after EDM is called a fire pattern.

28. What PL surface?
The PL surface is also called: the parting surface and the rake surface, which refers to the part where the front mold and the rear mold are in contact when the mold is closed. Mould Daren WeChat: mujudaren

29. What is the computer?
CNC milling machine and machining center

30. What is copper work?
EDM usually uses easy-to-process copper material as the discharge electrode. It is called copper work, also called electrode. Copper work is generally divided into: rough work, rough work, young work, and young workers.

31. What is the spark position usually?
During the discharge process, the discharge gap between the copper and steel materials is called the spark position, the rough spark is generally 10 to 50, and the spark point of the young worker is generally 5 to 15.

32. What is the material level?
The thickness of plastic products is also called thick meat.

33. What is the original body?
The original body is relative to the cutting insert, the original body is a piece of steel for the processing of the billet, processed together when processing.

34. What is the weld line?
The line formed by the encounter of two plastics is called a weld line.

35. What is the jet?
The flow of plastic that forms a curved fold-like snake from the glue inlet into the cavity is called a jet flow.

36. What is LKM?
LKM refers to the dragon record mold embryo, commonly used mold embryos are: LKM, Fu Deba, Mingli, Huansheng, Changhui, Desheng.

37. What does DME mean, what does HASCO mean?
DME and LKM are standard standards, DME is American, HASCO is European.

38, what is the reverse buckle?
The part of the product in which the front and rear molds cannot be directly demolded becomes an inverted buckle.

39, what is the foolproof?
Defence is a idiom that prevents a very simple mistake and prevents a daze! For example, an insert has a hanging platform of the same size on the side of the heaven and earth. When the site is assembled, it is likely to be installed on the side of the heaven and earth, but he is hanging on the side of the insert. It is impossible to install it, and it is impossible to install it wrong. This action to prevent the occurrence of a daze and a mistake is a daze.

40, what is a beer machine?
The beer machine is a local idiom, which is the injection molding machine and molding machine we often say.

41, what is the stop?
The mouth is the pinch art line, also known as the ugly line.

42. What is a flying model?
The flying mode is the matching die or the standard model.

43. What is a light knife?
The CNC finishing motion is called a light knife, which is to process it in place on an open basis.

44, what is the open box?
The action of machining the position of the mold core on the mold blank is called an open frame.

45, what is the sun word?
The sun type is the processing font that is placed in the film and then added to the font.

46, what is the opposite?
The method of turning the mold before and after the normal mold position is reversed is called reverse.

47, what is floating?
The part that has a partial buckle with a small insert is called a floating method.

48, what is the pre-meal?
When the mold is opened, the product remains in the front mold as the pre-meal mold.

49. What is white?
When the ejection is required, the mold force is large, and the thimble is not enough, so that the product is partially broken. From the front of the product, there is obvious white for the top white, which is also called the top water nozzle.

50, what is baking.
The mark left on the surface of the manufacturing point when diving into the water is called baking.

51, what is the code?
The dowel is a clamping tool, a pad with a triangular beveled open slot.

52, what is called cut?
Overcutting refers to excessive cutting, that is, when the workpiece is machined, the parts that do not need to be processed are also processed, and overcutting is not good. Mould Daren WeChat: mujudaren

53. What is the school cup?
The front mold pops up the inner position of the mold.

54. What is gums?
Tapping. The tapping thread is called the gums.

55. When do you need to make a two-color mold?
Design a two-color mold when a product contains two different materials or different colors from the same material.

56. What is the mold design process of the factory?
Customer provides product map → analysis product → confirm plastic variety → confirm mold material → transfer engineering drawing → take shrinking water as mirror phase → perfect group drawing → order mold embryo → order mold material → draft mode → 3D parting → determine flow path /Gate method→Structure design with reference to the layout diagram→Demolition and inserting→Correct 3D→Project drawing “including: mold core/insert/mold/distribution”→Do BOM → proofreading

57. How many ways to demould?
Shun and strong off the mold Daren WeChat: mujudaren

58. What are the feeding methods?
Directly enter the glue → lap into the glue → side glue → ring travel glue → sheet into the glue → latent → point into the glue → horn type into the glue → fan into the glue.

59. What are the forms of the runner?
There are circular flow paths → semi-circular flow paths → T-shaped flow paths → regular hexagonal flow paths.

60, the mold designer’s standing manual and books?
Steel books, plastic books, mold standard parts books.

61. What is the role of the spring?
Resilience occurs when external use occurs

62. Why should the mold be drafted?
Prevents the product from being pulled when it is released from the mold

63. What is the role of the screw and the length of the fit?
Mainly tightening and fixing, the matching length is generally 1.5 to 2 times the diameter of the screw.

64. How big is the slope of the slider? How much is the slope of the inclined guide column?

The slope of the slider is generally taken as: 20 degrees, and the inclination of the inclined guide column is generally 18 degrees.

65, the role of cold wells?
The function of the cold well is to store a small portion of the lower temperature plastic material that first enters the mold.

66, the role of the positioning ring?
The purpose 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 the match?
The cooperation is mainly divided into three categories: clearance coordination, transition coordination, and interference fit.

68. What is the role of the insert?
Convenient processing, prevent carbon deposits, facilitate polishing, save materials, help exhaust, facilitate replacement, and reduce processing machines.

69. What are the indicators of hardness?
Hardness indicates the ability of a material to resist the intrusion of a hard object into its surface. Commonly used hardness indexes are Brinell hardness, Rockwell hardness and Vickers hardness.

70. Can the surface be drafted? Can the group be drafted? Can the quilt be replaced?
The surface cannot be drafted, the surface can be drafted, and the quilt can be replaced.

71. What is the difference between the first corner method and the third angle method?
1. When placing an object in the first quadrant, the method of projecting the view by the relationship of {viewpoint} (observer) → (object) → (projection surface) is called the first corner method, also known as the first quadrant. law.
2. Where the object is placed in the third quadrant, the drawing method is projected by the {viewpoint} (observer)→(projection surface)→(object) relationship, which is called the third angle method, also known as the third quadrant method. .
Note: The difference between the first corner painting and the third corner painting is the article placed by the view.
The first corner drawing: the left view is placed on the right, the right view is placed on the left, the upper view is placed below, and so on…
The third triangle: the left view is placed on the left, the right view is placed on the right, the upper view is placed on the top, and so on… Mold Daren WeChat: mujudaren

72. What are the ways to transport water?
Commonly used for transporting water are: straight-through, wraparound, water tower, and spiral.

73. What are the basic principles of the three views?
The basic principle of the three views is: long alignment, high level and width.

74. What are the types of injection machines?
According to the shape; vertical, horizontal. According to the injection quantity, it is 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. That is, the injection volume ranges from a few milligrams to several tens of kilograms, and is divided into several to several thousand tons according to the clamping force.

75. What is the relationship between clamping force and modulus?
The clamping force of the injection molding machine is greater than the clamping force, otherwise the mold will open the pressure inside the mold.

76. What are the positioning methods of the male and female models?
There are two types of positioning methods for the front and rear modes: one is: template positioning, and the other is: mold 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, and the suitable wall thickness of NoryL is: 2-3.5mm

78, what is the overflow value?
The overflow value refers to the value of the plastic product that will overflow under the gap (that is, the running edge). The overflow value of ABS is 0.04mm, and the overflow value of pc is 0.06mm. The edge value is: 0.015mm, 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, and the overflow value of PMMA is: 0.065mm, the overflow value of PVC is 0.07mm, the overflow value of AS is 0.05mm, 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. How big is the standard frame?
Commonly used frames are: A0, A1, A2, A3, A4, A0 frame size is: 1189mx841m, A1 frame size is: 841mx594mm, A2 frame size is: 594mmx420mm, A3 frame The size of the frame is 420mmx297mm, and the size of the A4 frame is 297mmx210mm.

80. Planning for mold size?
Each company’s planning mold size standards are different, but the common standards are divided as follows: 15-30 series mold embryos are listed as small molds, 30-50 series mold cores are listed as medium molds, 50 or more The mold of the mold blank is listed as a large mold.

81. What is elastic deformation? What is plastic deformation?
The object is under the action of external force

/by

Casting and forging dies

In mold making, we usually hear casting and forging. What is the difference between the two manufacturing processes?

One casting

Casting is a process in which a metal is smelted into a liquid that meets certain requirements, poured into a mold, and cooled, solidified, and cleaned to obtain a casting (part or blank) having a predetermined shape, size, and performance. The basic process of industry.

The blank produced by casting has low cost, and it can show its economicality for parts with complicated shapes, especially those with complex inner cavity; at the same time, it has wide adaptability and good comprehensive mechanical properties. However, materials required for casting production (such as metal, wood, fuel, modeling materials, etc.) and equipment (such as metallurgical furnaces, sand mixers, molding machines, core making machines, falling sand machines, shot blasting machines, cast iron plates, etc.) It is polluted by dust, harmful gases and noise.

1. There are many kinds of castings, which are habitually divided according to the modeling method:

1 Ordinary sand casting, including wet sand type, dry sand type and chemical hardening sand type.

2Special casting, according to the modeling material, can be divided into special castings with natural mineral sandstone as the main modeling material (such as investment casting, clay casting, casting workshop shell casting, negative pressure casting, solid casting, ceramic casting). Etc.) and special castings with metal as the main casting material (such as metal casting, pressure casting, continuous casting, low pressure casting, centrifugal casting, etc.).

2. The casting process usually includes:

1 mold (to make liquid metal into a container for solid casting) preparation, mold can be divided into sand type, metal type, ceramic type, mud type, graphite type according to the materials used; can be divided into disposable type and semi-permanent type according to the number of times of use And permanent. The pros and cons of casting preparation are the main factors affecting the quality of castings;

2 melting and casting of cast metal, cast metal (casting alloy) mainly cast iron, cast steel and cast non-ferrous alloy;

3 casting processing and inspection, casting processing includes removal of core and casting surface foreign matter, refining riser, burr and burr and other projections, as well as heat treatment, shaping, anti-rust treatment and roughing.

2. Forging

Forging is a processing method that uses a forging machine to apply pressure to a metal blank to plastically deform it to obtain a forging with certain mechanical properties, a certain shape and size, and is one of the two major components of forging.

Through forging, it can eliminate the as-cast looseness and weld hole of the metal, and the mechanical properties of the forging are generally superior to those of the same material. For important parts with high load and severe working conditions in machinery, forgings are often used except for rolled sheets, profiles or welded parts that are simple in shape.

1. Forging according to the forming method

1 open forging (free forging)

The impact force or pressure is used to deform the metal between the upper and lower stellite irons (anvil) to obtain the required forgings, mainly hand forging and mechanical forging.

2 closed mode forging

The metal blank is subjected to compression deformation in a forging die having a certain shape to obtain a forged piece, which can be classified into die forging, cold heading, rotary forging, extrusion, and the like.

2. According to the deformation temperature

Forging can be further divided into hot forging (processing temperature is higher than the recrystallization temperature of the blank metal), warm forging (below the recrystallization temperature) and cold forging (normal temperature).

The forging materials are mainly carbon steel and alloy steel of various compositions, followed by aluminum, magnesium, titanium, copper and the like and alloys thereof. The raw state of the material is bar, ingot, metal powder and liquid metal. The ratio of the cross-sectional area of ​​the metal before deformation to the area of ​​the die after deformation is called the forging ratio. Proper selection of forging ratios has a lot to do with improving product quality and reducing costs.

/by

Mold forming process

Casting mold means that in order to obtain the structural shape of the part, the structural shape of the part is made in advance with other easily formed materials, and then the mold is placed in the sand type, so that a cavity having the same structural size as the part is formed in the sand type. A fluid liquid is then poured into the cavity, and the liquid is cooled and solidified to form a part identical to the shape of the mold.

According to different working conditions, it is mainly divided into the following types of processes:

1. Ordinary die forging:

Ordinary die forging is to place a heated or unheated metal blank in a mold cavity. Under the influence of impact or pressure. The geometry of the metal is varied to obtain a forging that is consistent with the cavity. Ordinary die forging includes hot forging and pier forging. Pier forging can also be divided into warm piers, cold piers, and hot piers;

2, squeeze:

Extrusion is the placement of a metallic material in an extruded mold cavity. Apply strong pressure to one end. The casting mold material is deformed in a state of being accepted in three directions. Thereby flowing out of the die hole at one end. Get parts of different shapes. Classified according to the direction of motion of the punch and material. Extrusion can be divided into positive extrusion, reverse extrusion, composite extrusion, radial extrusion and the like. According to the billet temperature, it can be divided into hot extrusion, cold extrusion and warm extrusion;

3, pull:

At the time of drawing, the material was pressed in both directions and was always pulled. Formed by casting a die hole in the mold. Obtain blanks, profiles, and parts of the required shape and size. Pulling can be divided into extubation, drawing, and the like. The products obtained by drawing have higher precision and lower surface roughness, and are often used for reworking of rolled bars and tubes to improve quality;

4, stamping:

Stamping is the use of a die to deform or separate the material. Thereby obtaining a processing method of the part. Stamping can obtain parts with complex shapes, good surface quality and high precision. Casting molds have high productivity and low cost, and stamping can be mainly divided into two types: forming process and separation process. The separation process includes punching, blanking, trimming, trimming, etc.; the forming process includes drawing, bending, expanding, tumbling, and schooling;

5, die casting:

Die casting is a process in which a molten metal is injected at a high pressure into a cavity of a die-casting mold at a high pressure and solidified under pressure to form a casting;

6, plastic molding:

The plastic molding is under the action of pressure, and the casting mold molds the powder or the heavier plastic in the mold to obtain a plastic product of a desired shape and size. Plastic molding can be divided into extrusion molding, compression molding, injection molding and other processes.

/by

What are the effects of lost foam coatings?

Lost foam casting has many kinds of processing methods in China. Different lost foam casting methods have different requirements on coating properties. The casting system and casting body have different requirements on the properties of the material. The gas permeability of the lost foam coating is accurate. It should be permeability, and the permeability of the medium temperature zone has practical value. In the selection of aggregates, the higher the refractoriness, the better. In order to ensure the good permeability of the sand, there are new requirements for the stripping property of the coating. The method of making and using the paint has an effect on the workability and process performance of the paint.

1, the role of lost foam coating

The function of the lost foam coating is to support and protect the foam model, prevent the liquid metal from infiltrating into the sand and sand, absorb the cracked product and allow the cracked gas to pass through the coating, keep the cavity air gap formed by the foam model cracking intact, and hold the liquid Metal heat does not dissipate quickly. Therefore, the use of the lost foam coating can reduce the surface roughness of the casting, ensure the accuracy of the casting, reduce or prevent the casting sand, sand holes, pores, metal penetration, cold insulation, pouring, carbon deposition and other defects. Therefore, the lost foam coating should have sufficient refractoriness, certain mechanical strength, proper thermal and thermal conductivity, proper gas permeability and ability to absorb liquid cracking products, smooth surface, sufficient coating performance, and no foam model. A chemical reaction occurs.

2, the performance of the lost foam coating

The properties of lost foam coatings include many indicators: strength, gas permeability, refractoriness, thermal insulation, rapid cooling resistance, rapid heat, wettability, thixotropy, varnishing, dripping, suspension, etc. These performance indicators can be Classified into two categories: work performance and process performance

Coating strength, gas permeability, refractoriness, thermal insulation, and resistance to rapid cooling and heat are all workability. The most important of these are strength and breathability. Lost foam coatings require high strength and high gas permeability, which is different from other foundry coatings.

The coating properties, dripping properties and suspension properties of the coatings are process properties. In order to reduce the cost of foam casting, water-based coatings are often used. Therefore, water-based coatings and organic foam moldings do not wet, and it is necessary to improve the coating properties of coatings, which is a major process performance of lost foam coatings. Another major process performance is the dripping of the coating. After the dipping coating, the pattern is generally suspended and dried. It is hoped that the coating can be leveled and not dripped as much as possible to ensure a uniform coating of a certain thickness, making full use of the coating without polluting the environment.

3. Composition design of lost foam coating

The basic components of the coating for lost foam casting include refractory materials, carriers, binders, suspending agents, preservatives, surfactants, defoamers, and the like.

Luoyang Liu’s mold reminds you to pay attention to: (1) the selection of coatings should be considered from the aspects of coating performance, preparation operation and procurement cost; (2) the permeability of coatings with alumina as the main aggregate is relatively high; (3) Poor gas permeability makes it possible to add a certain amount of organic binder and organic binder to burn in the foot-filling process to increase the micropores of the coating, which not only increases the gas permeability, but also increases the room temperature strength of the coating.

The above is the knowledge about the lost foam coating summarized by Luoyang Liu’s mold. For more details about the lost foam coating, please contact us.

/by