(1) Definition of defects

Discoloration, yellowing refers to the difference with the specified color of the product, the main local presentation of yellowing, blackening and so on.

(2) Cause classification

①Materials

1. The use of unsuitable color materials, heat resistance is not enough, resulting in the material in the cylinder has been sold or yellowing.
2. Dehumidification drying temperature is too high, or too long, so that the material itself discoloration.

② mold reasons

The gate is too small, and the injection process generates shear heat, causing the material to decompose.

③ Injection molding process reasons

1. Material is too high.
2. Retention time in the barrel is too long. c. Injection speed is too fast, and too much shear heat is generated during the flow process. d. There is an abnormal stoppage in the production process.

④ Hot runner causes

1. A.There is dead space in the hot runner channel.
2. B.The hot runner processing causes the material to stay for a long time.

(3) Solutions

①Material Countermeasures

1. Check the temperature resistance and thermal stability of the colorants or additives used.
2. Check the drying degree and time.
3. Check the temperature resistance and thermal stability of the colorants or additives used.

②Mold Countermeasures

Increase the gate or change it to another type of gate.

③Injection molding process countermeasures

1. Check the melt temperature and reduce the material temperature; reduce the screw speed and back pressure during plasticizing.
2. Check the injection volume and make sure that the correct plasticizing unit is used.
3. Reduce the injection speed to reduce the shear heating phenomenon.
4. Make sure that there is no prolonged shutdown during the production process, and when shutdown, the temperature of the barrel needs to be reduced.
5. Check the temperature of the barrel.
6. Check the temperature of the barrel.
7. Check the temperature of the barrel.
8. Check the temperature of the barrel.
9. Check the temperature of the barrel and make sure that it is not too hot.

④ Hot runner countermeasures

1. A. Improve the hot runner channel to eliminate the dead space.
2. B. Polishing the hot runner channel.
3. C. Polishing the hot runner channel.
4. D. Make sure that the hot runner channel is not too hot.
5. —- The above content is selected from “Injection Molding Use of Technology”, thank you for your attention to Fomtec Machine!

• Definition of defect

Eccentricity of product bore refers to the phenomenon that after injection molding, the bore of the product will produce a difference in wall thickness from the design, with one side being thin and the other side being thick.

• Classification of causes
• Product design reasons

1. The product itself has the structure of designing long core, which causes the risk of congenital eccentricity defect.
2. The long core structure of the product does not take into account the structural design to prevent eccentricity.
3. Mold causes
4. There is a large eccentricity in the processing of the long core of the mold, causing the product to deviate to one side.
5. The long core of the mold is not designed with a cooling system, and the high temperature during the production process causes the long core of the mold to deform to one side and become eccentric.
6. The strength of the long core insert is not enough to withstand the injection pressure.

• Causes of injection process

1. The injection pressure is too high, and the long core insert of the mold is punched off.
2. The injection speed is too fast, so that the molten material is extruded to one side, and eccentricity is formed.

• Solution
• Product design countermeasures

1. Avoid the design of the long core structure of the product and use the structure of the insert instead.
2. Long core products to do touch through the structure to prevent eccentricity.

• Mold countermeasures

1. Improve the precision of mold processing, design the mold structure that can adjust the eccentricity of the long core.
2. Enhance the cooling effect of the mold long core inserts.
3. Mold long core insert design is relatively large to ensure the strength.

• Injection molding process countermeasures

1. Low pressure injection.
2. Low-speed injection first, to ensure that the long core inserts are surrounded by materials before high-speed injection.

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• Definition of defect

Product weight instability (injection molding instability) means that the weight of a plastic product is unstable or fails to reach a set standard weight, and is accompanied by variations that are out of range.

• Classification of causes

• Material reasons

1. Plastic material impurities, and impurities in the density of the material used than the density of the material is smaller, so the weight of the melted material there are differences.

1. Plastic drying degree is not enough, the water content is too large.

1. Plastic quality is unstable (there is the addition of recycled materials).

1. Plastic material is not stable.

1. Plastic material is not stable.

1. Plastic material is not stable.

1. Plastic material is not stable.

1. Material is not stable.

1. Material is not stable.

1. Material is not stable.

• mold reasons

1. The gate is too small, resulting in the inability to fully fill the mold cavity.
2. Mold temperature is uneven or low.

• Injection molding process reasons

1. Insufficient back pressure pressure of molten plastic, resulting in gas inside the material, moving the same number of positions, the weight is small.

1. Hopper feeding is not stable, part of the corner of the material hollow, resulting in deviation.

1. Insufficient injection time, not filled, the set injection time has been used. d. Insufficient holding time and pressure.

• Reasons of injection molding machine

1. . Wear and tear of the stop ring of the injection molding machine, during the process of injection, there is a phenomenon of backflow of the melt, resulting in an unstable injection volume.

1. Variation of the melt volume of the metering stroke or the material pad.

1. Insufficient clamping force, in which case the weight of the product increases.

1. Inadequate clamping force.

1. Inadequate clamping force.

1. Inadequate clamping force.

1. Inadequate clamping force.

1. Inadequate clamping force.

• Solutions

Material Countermeasures

1. Use pure raw materials and clean production equipment to prevent impurities.

1. Dry the material sufficiently.

1. Use pure raw materials with no add-backs.

1. Use a clean production facility.

1. Use a clean production facility.

1. Use a clean production facility.

1. Use a clean production facility.

1. Use a clean production facility.

1. Use a clean production facility.

②Mold Countermeasures

1. Increase the gate.
2. Adjust the mold temperature.
3. Use pure raw material without adding back material.
4. Adjust the mold temperature.
5. Adjust the mold temperature.

• Countermeasures of injection molding process

1. Increase the back pressure of the molten material, exhaust the gas in the barrel, and compact the molten material at the same time.
2. Remove the hopper for checking and unclogging.
3. Extend the injection time.
4. Extend the holding time and increase the holding pressure.
5. Increase the pressure.
6. Increase the pressure.
7. Increase the pressure.
8. Increase the pressure.
9. Increase the pressure.
10. Increase the pressure of the injection machine.
11. Increase the pressure.

• Injection molding machine countermeasures

1. Replace the injection molding machine parts.
2. Detect the stability of the equipment.
3. Adjust the clamping force or replace the large tonnage of the injection molding machine.

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• Definition of defect

Deformation (warping, twisting) refers to the plastic parts in the injection molding, the material in the mold is subjected to high pressure and internal stress, demolding, the shape of the injection molded product deviates from the shape of the product design and the shape inherent in the mold cavity, the plastic products injected into the shape of the dimensions of the size of the product design and the size of the larger differences (shrinkage warping), and irregular bending occurs

• cause classification

• Operational reasons for bad habits.

Ejecting the product, the operator does not place according to the regulations, the product has not been completely cooled, may have produced warpage.

② Design reasons product structure design is unreasonable,

wall thickness difference is large or too thin. The shape and structure of the product is unusually complex.

③ Material reasons

1. Excessive water content of plastic (incomplete dehumidification and drying).

1. Incorrect prediction of plastic shrinkage (mold pre-shrinkage).
2. Poor fluidity of the material. d . Improper ratio of additives added to the material.

④ Mold causes

1. Large temperature difference between front and rear molds.
2. Mold temperature is too low.
3. Cavity thickness difference is too large.
4. Improper number or location of gates.
5. Sprue too small, runner too long.
6. Uneven ejection. The product is not completely cooled when ejected, the product is easy to warp or the thimble position is not properly selected.
7. Inappropriate design of cooling water circuit, uneven cooling efficiency.

⑤ Causes of injection molding process

1. The barrel temperature is too low. When the barrel temperature is too low, the melting temperature is low, the residual shear stress is large, and the product is easy to warp.
2. Nozzle temperature is too low. Nozzle and mold contact parts to take away too much heat, the material temperature will fall, barely high speed molding, residual shear stress is large, easy to warp.
3. Injection pressure is too high.
4. Holding pressure or holding time is not appropriate.
5. Improper cooling time.
6. Insufficient slow charging.

• Solution

• Operation countermeasures to put the product into the designated location, standardize the operation.
• Product design countermeasures to change the product thickness design, to ensure that the wall thickness can withstand the deformation force of the product, or to do the structural design of the pre-distortion correction to improve the warping phenomenon.

• Material countermeasures

1. Check the dryness and water content of the plastic.
2. Check the plastic molding shrinkage, compare the material supplier’s suggested value with the actual shrinkage of the difference, or do pre-distortion on the mold to correct the material shrinkage and deformation.
3. Select high quality and good strength materials. Generally, the lower the density of the plastic material, the greater the shrinkage deformation of the product for reference of material selection.
4. Adjust the ratio of material additives appropriately.

• Mold countermeasures

1. Minimize the temperature difference of the mold.
2. Mold temperature should reach the range required by the material.
3. Adjust the mold design structure to reduce the difference.
4. Perform a mold flow analysis on the product to reconfirm the reasonableness of the gate location.
5. Increase the runner or reduce the number of cavities.
6. Reasonable design of ejector position.

• Countermeasures for injection molding process

1. Increase the material temperature.
2. Increase the nozzle temperature.
3. Reduce the injection pressure.
4. Decrease the holding pressure and shorten the time.
5. Extend the cooling time.
6. Lengthen the buffer.

—- The above content is selected from “Injection Molding Use Technology”, thank you for your attention to Fomtec Machine!

• Definition of defect

Uneven ejector pin position means that after injection molding, the ejector position of the product has either high or low ejector marks, thus affecting the appearance or assembly function of the product.

• Classification of causes

①Mold causes

 a The thimble itself has a false position or is loose after assembly.

 b The height of the thimble is higher or lower than the mold cavity surface.

 c The return spring force is too large, causing deformation of the ejector plate, and all the ejector pins cannot eject the product at the same time.

② Injection molding process reasons

 a The ejector pressure is set too high, and the ejector plate is deformed.

 b The number of holes in the ejector stick is not enough, resulting in deformation of the ejector plate and unbalanced ejection.

③ Injection molding machine reason injection molding machine template has been deformed, the level of deviation, resulting in the difference between the sky side or the ground side of the ejection.

• Solution

①Mold countermeasures

 a Improve the precision of mold processing to ensure that the ejector pin is fixed.

 b Improve the mold processing accuracy and deformation. Ensure the consistency of the ejector pin height.

 c Use a smaller spring force or thickened ejector plate, hardened ejector plate to prevent

②Injection molding process countermeasures

 a When making sure that the product can be ejected, use a smaller ejector force and slow down the ejector speed. b Increase the number of ejector holes to make sure that the ejector can be used.

 b Increase the hole of ejector stick to ensure the balance of ejection.

③ Injection molding machine countermeasures Replace the injection molding machine production or repair the template to ensure the level.

—- The above content is selected from “Injection Molding Use of Technology”, thank you for your attention to Fomtec Machine!

• Definition of defect

Air streak refers to the localized presence of stripes or lumps of flow marks on the gate area or surface of the product, thus affecting the appearance of the whole product.

• Classification of causes

• Product design reasons

1. The wall thickness of the product is too thick, causing the internal gas to float out of the surface.
2. Complex structure, so that the gas can not be completely discharged.

• Material causes

1. Poor fluidity of the material.
2. Too little lubricant.

• Mold causes

1. The gate size is too small, resulting in slow flow rate.
2. Reasonable location of the gate.

• Causes of injection molding process

1. Low injection pressure and slow speed.
2. Injection time is too short.
3. Material temperature and mold temperature is too high, resulting in too good material flow, gas can not be discharged in time and formed gas pattern.

• Solutions

• Product design countermeasures

1. Adjust the product wall thickness.
2. Simplify the product structure.

②Material countermeasures

1. Replace the material with good fluidity or add additives.
2. Add lubricant.

③Mold countermeasures

1. Increase gate and runner size.
2. Change the location of the gate.

• Countermeasures for injection molding process

1. Increase the injection pressure and speed.
2. Extend the injection time appropriately.
3. Reduce the material and mold temperature.

—- The above content is selected from “Injection Molding Use of Technology”, thank you for your attention to Fomtec Machine!

For any injection molding plant, the direct way to increase production is to shorten the injection molding cycle time. Under the premise of guaranteeing the quality of the products, the shorter the injection molding production cycle, the more products will be produced. So, what is the concept of injection molding production cycle? How to set the right injection molding machine injection molding cycle?

What is the concept of injection molding production cycle?

Injection molding production cycle, also called injection molding cycle, is the production of an injection molded product time required. Generally speaking, the injection molding production cycle includes three parts: injection time (including mold filling and pressure holding), in-mold cooling time, mold opening time and mold closing time.

Expressed by the formula as follows:

Molding cycle = injection time + in-mold cooling time + mold opening time + mold closing time

How to set up a suitable injection molding production cycle?

If the fully automatic injection molding machine that relies on the robot to take parts, there is no human factor to open the safety gate and close the safety gate, it is controlled by the time setting, which can be used to ensure that the moving template in the small inertia impact and protection of personal and mold safety conditions, you can try to minimize the short time setting; non-full-automatic injection molding machine type, then in the opening and closing of the mold can be strengthened in terms of the operator’s training, guidance and supervision, requiring that the operator in the When the time arrives, the safety door should be quickly knocked open or closed, and try to make each stay for an equal amount of time, otherwise, the accumulated time error will also affect the thermal history of the plastic.

Injection time, injection pressure and screw metering time should be based on the nature of the polymer, products and molds, it is related to the injection pressure, injection rate, screw rotation, back pressure, temperature and many other factors, should be guaranteed under the premise of quality to seek a stable time. The number of screw rotation and back pressure directly affects the metering time of the screw, and the use of special screws will reduce the program time.

In terms of cooling time, the setting of cooling time should take into account the nature of the polymer, the product and the temperature and other conditions, while the actual cooling time of the product is included in the injection holding pressure and screw metering time, so that the injection molding process can be completed within the required cooling time of the product.

For what is the injection molding production cycle, how to shorten the injection molding production cycle, we know how to improve production efficiency for you !

What are the common tonnages of injection molding machines? It is worth mentioning that the tonnage referred to here is not the weight of the injection molding machine, but the clamping force of the injection molding machine. This point is a lot of injection molding novice will understand the wrong, we can take a small notebook to write down. And specific knowledge about the tonnage of the injection molding machine, please listen to our explanation.

What is Injection molding machine tonnage ?

Injection molding machine tonnage refers to clamping force, clamping force refers to the injection molding machine clamping mechanism applied to the mold clamping force. Speaking of clamping force, we will naturally talk about its corresponding melt pressure. When the melt pressure is too large, greater than the clamping force, then the force will be the mold open, the product can not be completed production. So in order to ensure that the product molding meets the accuracy requirements, the clamping mechanism must have enough clamping force to clamp the mold.

What are the common tonnages of injection molding machines?

The processing capacity of an injection molding machine depends on two parameters – injection volume and clamping force. Therefore, the tonnage of the injection molding machine affects the processing capacity of the injection molding machine, according to which the injection molding machine is divided into smaller, small, medium, large and larger. The detailed classification can be seen in the following table.

Clamping force (tonnage) and injection volume, also reflects the size of the injection molded products, is an important parameter of the injection molding machine, is to ensure the quality of plastic products is one of the important conditions. As a result, many countries and regions use clamping force as the standard of injection molding machine specification.

The average pressure of the mold cavity corresponding to different sizes of injection molded products

PE, PP, PS and other thick-walled and uniform easy-to-mold products, generally used in the average pressure of the mold cavity for 25 MPa; mold temperature is higher under the conditions of molding thin-walled containers, generally used in the average pressure of the mold cavity for 30 MPa; ABS, POM and other precision requirements of high precision parts, the viscosity of the material and the precision of the requirements of the high, generally used in the average pressure of the cavity for 35 MPa; High-precision mechanical parts, such as plastic gears, these products have high viscosity, difficult to fill the mold and high precision requirements, the average pressure of the mold cavity is generally selected for 40-45 MPa.

Above is the introduction of tonnage for injection molding machine,we hope it can help you.

Throughout the current injection molding industry, it is not difficult to find a certain scale of injection molding factory, are beginning to automation, unmanned plant direction. The implementation of automation and unmanned injection molding can reduce the problem of adjusting the machine caused by the instability of manual start-up, and under the premise of mass production, it can also reduce the expenditure of production.

So, what is injection molding machine automation? How to realize the injection molding machine automation? For the above questions, the following Fengtie Jun to answer for you one by one.

What is injection molding machine automation?

Injection molding machine automation, that is, relying on injection molding robot to replace the use of manual, injection molding robot use can significantly increase productivity and reduce production costs, can stabilize and improve the quality of injection molded products, to avoid losses caused by human error.

Traditional injection molding manual mode of low efficiency, safety hazards has been unable to meet the needs of society and customers, various enterprises and factories have to seek breakthroughs, slowly joined the injection molding automation team.

How to realize the injection molding machine automation?

For how to realize the injection molding factory automation, I believe many people only think of the injection molding machine with a robot. And the reality is that if you want to realize the injection molding factory unmanned and automation, in addition to the need to invest in robots, we also need the central feeding system, conveyor belts, sensing technology and intelligent industrial software and other technologies.

Injection molding factory automation can make low-tech, simple repetitive, high-intensity labor with machinery to complete, and then supplemented by conveyor technology to make all the injection molding products transported to the environment of a comfortable air-conditioned operating room, so that the original workshop busy logistics has become smooth, but also to make the original night lights bright injection molding workshop do not even have to open a light.

Automated injection molding factory have what industrial control equipment?

1、Controller — the brain of the automated factory

2、Robot — the firm executor of the automation factory

3、Servo motors—-the muscle of automation factory to provide power.

4, sensors — automation factory feel the touch of external information

5、Frequency inverter—-the energy saver of automation factory

6、Solenoid valve—-the tendon of automation factory

7、Industrial camera—-the vision of automation factory

8、Instrumentation — the pulse of automation factory

9、Automation software—-the thinking of automation factory

10、Control cabinet

The injection molding machine automation equipment is a high-end product, if it is a small factory then want to buy this batch of equipment, you have to prepare the funds enough to do; and relative to some manufacturing group enterprises, it is necessary to seize the opportunity to complete the transformation and upgrading at an early date.