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Rival the cycle of rotary compression molding with

HASCO Collapsible Core

Below are a few of the reason to consider HASCO collapsible cores for closure molds.


1) Instant venting as the core begins to collapse. Cycles times are extended with the unscrewing core because the vacuum caused as the core unscrews drawing in the top deck resulting in dome sink. By venting this issue is removed from the equation.

2) No unscrewing ratchet teeth are required. This is another reason cycles are extended. The side wall needs to solidify enough that the teeth do not tear through the side wall during unscrewing. Another defect with the teeth is the fines that are sometimes left as the teeth dig into the part. The collapsible core eliminates this defect.

3) The core is cooled. In some cases the center cores have no water such as the tamper evident style closures. The hot core can then influence the cycle, extending it. The collapsible core has cooling in the center and the segments are in close contact allowing the heat to be conducted through the segments and into the center core.

4) The collapsible cores operate during the ejection stroke. For an unscrewing core, the rack needs to be activated and then reset. This down/up motion adds at a minimum 0.7 seconds (this is quite fast and the molds that I saw running the full down/up cycle at this speed were subject to frequent maintenance) to a more normal 1.5 to 2 seconds to the cycle plus the ejection stroke.

Estimated cycle savings due to above in comparison to a closure running approximately a 10 second cycle:
Items 1- dome sink and 2-unscrewing teeth - 1.0 seconds
Item 3 - Cooling in core ---------------------------- 1.0 seconds
Item 4 - No rack to move -------------------------- 1.5 seconds

The above totals 3.5 seconds. This takes the cycle from 10 to 6.5 seconds with a hot tip. By using the valve gate the hold time is reduced to wait for the gate freeze. Let's estimate 1.0 second for the use of a valve gate. Now the cycle is down to 5.5 seconds.

So by using these conservative estimates, using the collapsible core with a hot tip should be able to reduce a closure cycle time by 20% to 30%. Using a valve gate on the closure should help reduce that cycle time further achieving a cycle reduction of 40%to 50%. Press type and condition as well as other part features can and will alter the cycle savings but there is a great opportunity to reduce cycle by using the collapsible cores.

Some things not mentioned are the opportunity to reduce wall section. The part would not need the wall strength in the hot state during ejection and the parts can be straight walled on the core side and minimal draft on the cavity side.

As you see, there is a great opportunity to reduce cycle, reduce part weight, or reduce cavitation of the mold to produce the same amount of parts.