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Tandem Molds

Also known as toggle molds or T molds, tandem molds are a variation of a stack mold, with alternately filled layers. While one layer is filling and molding parts in its cavity (or cavities), the other layer is ejecting its part(s). This plastic injection mold design allows for different parts and designs to be run in each layer, using different shot sizes or plastic volume in each half. The popularity with this mold type is with family parts for assembly and longer cycle time components.


Tandem Mold Additional Features


When you want to improve your cycle times and reduce your press time on slow cooling parts, a tandem mold is the way to go. 


Tandem molds enable you to overcome common conventional molding challenges by addressing:
  • Slow cycle times
  • Producing more parts and volume, with small shot sizes
  • Family components produced simultaneously from a single mold
  • Different fill rates
  • Wide variety of solutions through thermal gating

Tandem molds are similar but different from stack molds, where one cavity is being filled at a time.

Want more information or a little confused; our team can walk you through the options and benefits.  Contact us.

Tandem Mold Customer Example

The customer’s part was taking too long to cool, thus wasting valuable press time and money.  A1 engineered a tandem mold in order to run two parts in sequence from the same press and from the same mold.

Large Increase in Capacity Example
  • Part Height:  2.8”
  • Material:  Polypropylene
  • Part Weight: 7.5 lbs.
  • Shrink:  .007/inch
  • Total mold weight:  18,000 lbs.
  • External Mold Dimensions:  L 49” x  W 36” x H 43”
  • Old Cycle Time: 70 seconds
tandem mold
White Paper


Stack molds can increase productivity by up to four times in some cases. See how in our white paper.

Engineering Experience Quality

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