How to Speed Up Cycle Time for Injection Molded Plastic Parts?

Experienced injection molding machine manufacturer can anticipate factors that potentially increase cycle time — like thin steel and hot spots — and proactively prevent them by offering design change options. Calculating cycle time takes many factors into consideration:

PLASTIC TYPE
The chemistry behind the construction of a plastic also underlies cycle time calculations in important ways. Certain polymers, for example, don’t solidify as quickly as others. If chosen for constructing a certain injection molded part, that extra time translates to longer times in the mold cavity, and thus extended cycle times.

PART DESIGN
If an injection molder is looped into the design phase, chances are greatly improved that cycle time missteps will be avoided. Certain design parameters like wrapping plastic entirely around a steel component or another non-flat configuration, designing a mold that cannot accommodate cooling lines, or including unduly thick walls, drives up cooling times.  An injection molder that’s previously been through and resolved these kinds of struggles will offer invaluable guidance during the design phase.

MOLD MATERIAL
Like plastics selection and part design, mold material influences outcomes. Steel is the most common mold material used in injection molding machines, but there are occasions where heat must be pulled out of the molded plastic faster than steel allows. In these instances, aluminum or other highly-conductive metals may be inserted within the steel tooling so it comes into strategic contact with the plastic to address potential hot spots without interrupting molding or delaying cycle times.

MOLD COOLING DESIGN
Designing the mold to include cooling lines that run through the steel to cool the molded plastic is a typical solution. Injection molders that conduct moldfill analysis to estimate how long it will take that part to reach ejection temperature may encourage the use of cooling lines — or changes to cooling design systems, water temperatures, or flow rates — to optimize the overall molding cycle. 

Overall, this means that you can achieve higher productivity at reduced costs. more importantly? From the accuracy of parts cost and sales forecasts during the planning stage to the availability of parts to meet order fulfillment requirements, accurate cycle time estimates give injection molding machine manufacturers confidence in their production schedules.