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Mold common problems

August 17, 2021

  1. Raw edges
  2. a) Confirm whether the number of frames and clamping forceof the injection machine are sufficient
  3. b) Confirm whether the pressure is too high

1) If the unsaturated sample still has burrs, it means that the mold clamping is not good or the fault is broken.

2) If the mold clamping is not good and the size is too small when the pressure is reduced, the size problem needs to be confirmed

  1. c) Poor clamping → re-closing


  1. Breaking


Poor discharge positioning of male and female molds or wrong electrode size → put them in place again (need to evaluate the difficulty of mold repair, whether

(Under the influence of function and appearance, the size can be allowed to be larger)

mold trial

  1. Pull the male mold (deformation)


  1. a) Insufficient lighting (scratches, whitening or deformation) → Strengthen lighting
  2. b) Insufficient draft angle → The draft angle can be increased without affecting the function or shrinking the appearance.
  3. c) Insufficient ejection, unevenness → add ejector pin or change ejection position
  4. d) Poor positioning of ejector slippage → Ejection head bites to increase friction
  5. e) The injection pressure is too large (especially near the inlet, the inlet position is poorly selected or the meat is too thin to obstruct the flow)

→Change the feeding position or increase the thickness of the meat to help flow (if the appearance does not shrink and does not affect the function)

  1. Pull the master mold
  2. a) Mold undercut:

(1) Design error → change design

(2) Construction error→modify mold


  1. b) Poor biting:

(1) Bite the flower barb → light up, heavy bite or partial bite

(2) Overbite → lighting

(3) Bite too deep and draw the flower (the thickness of the bite, the depth needs to match the draft angle) → polish, heavy bite or partial bite, change the draft angle if necessary

  1. c) After biting the flower, the pull of the male mold is insufficient → the male mold bites the flower or pushes out the pin to bite the flower to pull it back
  2. Punching shadow


  1. a) The rate of fire at the inlet is too fast → reduce the rate of fire or enlarge the inlet, but do not make the size too large to shoot


  1. b) The cold slug well is not good → Take a mold with four holes as an example, the cold slug well x3 and the cold slug head x2 must be large enough


  1. The fusion line is obvious (painting can be overwritten)


  1. a) The mold temperatureis too low → adjust the mold temperature (but it needs to be within the scope of appropriate mass production)
  2. b) Insufficient disturbance → the male model bites coarse flowers above MT11030, and the flow is disturbed
  3. c) Insufficient air escape → Strengthen escape air (add air escape blocks or injects, etc., if necessary, escape air burrs)
  4. The position of the fusion line causes the parts to break easily


If the fusion line cannot be eliminated

  1. a) Adjust the adjustment button to control the uneven feed volume to shift the fusion line
  2. b) The feed inlet is shifted


  1. Broken shadow


Excessive fluctuations in the height of the public model (insufficient differentiation) cause àincrease the differentiation area (be careful of interference problems) The public model bites the rough flower and has disturbed the flow


  1. The gloss is different


  1. a) Check whether the mold cavity is greasy → scrub
  2. b) Check whether the mold cavity is affected by the adhesion of the rubber mold caused by the high mold temperature → scrubbing
  3. c) The mold temperature is wrong, the higher the temperature, the more foggy → adjust the mold temperature, adjust the temperature while shooting, and hit the color difference
  4. d) Encapsulation due to poor air escape → Strengthen the escape of air near the enclosure or the flow channel


A If at the biting position:

  1. a) The thickness of the bite is the same as the depth. àCompared to the old parts and samples. b) Sandblasting error→Re-spraying
  2. Lighting part:
  3. a) The number of polished numbers is incorrect.
  4. The color difference is different
  5. a) Confirm resin
  6. b) Adjust the mold temperature
  7. Air bubbles (transparent material)
  8. a) Poor escape gas → Strengthen escape gas (flow channel, escape gas block or burrs when necessary)
  9. b) The rate of fire is too fast → adjust the machine
  10. c) The injection pressure is too small → adjust the machine
  11. d) The inlet or runner is too small
  12. e) Insufficient drying of rubber particles
  13. The clamping line is obvious


  1. a) Poor clamping → re-closing
  2. b) Male and female mode breakage → (refer to breakage handling)


  1. Poor filling:


  1. a) Confirm the mold temperature and whether the material temperature is too low and affect the fluidity b) Whether the shooting speed and the shooting pressure are too low
  2. c) Is the inlet flow channel appropriate (large enough, wide enough, and deep enough?) d) Is the exhaust gas sufficient?
  3. e) Whether materials can be stolen (non-structural parts should be stolen as much as possible)
  4. Shrink
  5. a) Confirm whether the holding pressure is sufficient (if the mold burrs have occurred, the gauge pressure has been too large) b) Confirm whether the thickness of the shrinkage is too thick àStealing meat or adding materials nearby


  1. a) Whether the injection pressure is too large b) Whether the full pressure is too long  c) The temperature difference between the male and female molds is wrong d) Whether the ejection is bad

16.Thimble Shadow

  1. a) Confirm the time when the thimble shadow appears, before or after ejection?

Before ejection: The top plate of the mold is insufficiently rigid and deformed due to pressure After ejection: The meat is too thin or the ejection is too deep or too shallow


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