2 Ways To Save Time And Materials When Changing Colors In An Injection Mold

For injection molding companies that offer products in different colors, switching between colors can be time consuming and expensive. Getting all of one color out of a mold before another is put into it stops production and uses valuable materials. If you run an injection molding company, here are two ways you can make the transition from one color to another more efficient.

Produce Different Colored Products on Different Days

Whenever possible, a color change should be planned to take place at the end of one work day and beginning of the next.

Your molds should be purged before they're shut down at the end of each workday. By switching between two colors between days, you can clean your equipment of the first color when the day is over and you'd be purging your machines anyway. The next workday, your machines will be free of any colors and ready to start a new run of products in a different color. Instead of cleaning the machines twice on the first day, once to get the first color out of them and once at the end of the day, you'll only have to clean them once.

To make sure your equipment is ready to start up with a new color on the next day, be sure to clean the following:

  • the injection molds
  • the hopper
  • the conveying system
  • the nozzle

All of these should be cleaned at the end of the day anyways, to prevent the materials in them from building up on your equipment or degrading. Thus, even though there's a lot to clean when switching colors you won't add any time to your end-of-day processes.

Use a Higher Temperature to Clean Out Injection molds

When switching between colors , you'll need to get all of the previously colored materials out of your injection molds. If you don't, the first color may contaminate the second, especially if the first color was darker than the second is.

The easiest way to clean a mold of a former color without shutting the mold down for a thorough cleaning is to run material that's the new color through the mold. The material will melt any leftover material that's in the mold. You'll have to discard the first few pieces produced, but, after these, there won't be any material leftover from the former color in the mold.

When running a new color through an injection mold to rid the mold of any remaining material that's a different color, you can increase the temperature of the material you're putting into the mold. This will help the new material melt any old material left in the mold quicker, which will reduce how many run-throughs you'll need to do to get your equipment clean of all material that's a former color.

For instance, instead of running newly colored material through three times, you may be able to get all of the material that's a different color out with just two run-throughs. This would reduce how much time and material changing colors uses by 33 percent.

Michael Seep notes that changing the temperature of materials in an injection mold can significantly affect their quality. In his experiment, products produced at 400 degrees Fahrenheit were more resistant to impact than those produced at 480 degrees Fahrenheit. Since the first few products will be contaminated by another color and discarded, however, you don't need to worry about the quality of these first few products. Once your equipment has been cleaned of all the material that's a different color, you can return the temperature to the proper setting and begin molding products that won't be thrown out.

Plan Your Color Changes

If you regularly produce otherwise identical parts that are different colors, consider how many materials and how much time is devoted to changing between colors. This may be an unavoidable expense for your injection molding company, but you can keep the associated costs under control by planning ahead. Try to change colors between workdays and increase the temperature of your material when using it to clean out old material. You should be able to save both time and money -- which will help your company's bottom line.