B.tech Project - Determination of Warpage in Injection Molded Plastic Components using Image Processing


Applying efficient and easy methodology for predicting warpage in plastic components.

Problem Definition

  • Plastic injection molding is one of the major net-shape-forming processes for thermoplastics materials. Mold temperature, injection pressure, filling time, injection speed are the four major parameters in manufacturing the injection molding components. 
  • There are several defects that occur in the injection molding process, including blush, blow holes, burn marks, warpage, bowing, bubbles, clear spots, cloudy appearance, contamination and cracking. 
  • Warpage is the possible defect which occurs with the variation in rate of solidification due to change in temperature differences in plastic components. 
  • Image processing technique is more convenient to predict warpage in injection molded plastic components. 
  • By minimising the warpage, considerable improvement in the performance characteristics of injection molded components can be observed. 


  • Preparation of fixture for taking steady images of plastic components.
  • production of forward and reverse lever ( FR lever ).
  • Warpage determination in FR lever using image processing technique in MATLAB.
  • Applying the same methodology to other plastic components like bottle caps and computer speakers.


          This work focused on determination of warpage for injection molded plastic components through image processing technique. In this context, a fixture has been prepared to capture digital images of plastic components in a fixed plane. Further this fixture helps to capture clear standby images of plastic components which help to get to more accurate warpage results using image processing. This work undergoes for determination of warpage in Forward and Reverse lever (FR lever), bottle caps and computer speakers. The two plastic components images are captured by using high resolution digital camera which are fixed in fixture. The high resolution captured plastic components of images, are processed using MATLAB Image Processing Tool. The distoreted injection molded plastic component is compared with the standard component by measuring at three different locations in longitudinal direction and also in lateral direction. Warpage has been calculated by taking the average of differences between those measurements in both directions. The warpage may be minimised by suitably selecting the process parameters of injection molding machine.


warpage in FR lever by using image processing

Warpage in FR Lever


  • In MATLAB, image processing tool is very effective and fruitful in the determination of warpage in plastic components. The present method used for measuring warpage is easy, time saving.
  • If warpage is more than the acceptable limit, suitable process parameters of injection molding machine such as mold temperature, injection pressure, injection speed, filling time and cooling time can be adjusted to get the better quality of plastic component.

  • Project guide : Dr G Padmanabhan, Si Venkateswara University.
  • Mr. S Selvaraj helped in production of FR lever and provided guidance.
  • Mr. Sudhakar provided support in MATLAB code for image processing.
Project team members :
B R Silpa Sree
N Sai Mohan reddy
Y Purushotham 
I thank above all for their guidance and amazing time during this project work.

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