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Chinese-Simplified NEW · ZC COLLAPSIBLE CORE
The most advanced solution to demold internal threads & undercuts
Custom-engineered collapsible cores, supplied ready to install, for parts from ø6 to ø400 mm.
Free project consultation
shorter cycle times
diameter range
cycles with DLC coating
Key benefits
Ready to install, optimized construction
Supplied as a complete assembly, minimizing additional machining and assembly work. Custom-designed to meet the specific part and mold requirements.
Compact design
Helps reduce the space required inside the mold. In multi-cavity molds, the compact design also allows for reduced spacing between components.
Shorter cycle times
Unlike unscrewing molds, CUMSA’s collapsible cores allow demolding to start before the part fully solidifies because the core collapses away from the undercut during ejection. This reduces cooling requirements and shortens overall cycle times by approximately 33%.
Simple maintenance
Easy construction and integrated safety features facilitate handling and maintenance.
Long service life
Available in standard and DLC-coated versions.
Need help incorporating CUMSA products?
Contact our team at technical@cumsa.com for a free project consultation.
PRODUCT OVERVIEW
A collapsible core engineered for every part
A custom-engineered collapsible core designed to demold complex undercuts, threads and other negative geometries in injection-molded parts. Each core is individually designed according to the part geometry and project requirements and supplied ready to install. Suitable for single-cavity and multicavity molds.
Configurations & size range
The required configuration depends on the diameter, depth and geometry of the feature to be released. The different combinations of the segments allow demolding parts from ø6mm to ø400mm.
6 segments
The standard solution. Can make undercuts up to 12% of its diameter.
8 segments
It can create undercuts of up to 14% of its diameter. It can also go up to 23% if the mold has a double-ejection system.
12 segments
Best suited for special solutions. It can make undercuts up to 14% of the diameter.
Possible geometries
Internal threads and blind nuts, open on both sides. Threads impossible to produce with unscrewing molds.
SYSTEM FEATURES
Integrated safety stop
Integrated into the corners of each collapsible segment. Prevents possible segment to segment collision eliminating the risk of damage when fully opened or in case of overtravel.
Retaining rings system
Retaining rings can be supplied with square, stackable or round formats, depending on the available space and mounting requirements.
Square format
The most common, with 4 mounting holes.
Stackable format
Several collapsible cores share a common retaining ring, minimizing the space needed in the mold and reducing its overall size.
Round format
Available with 3 or 6 mounting holes.
Collapsible parts
MATERIALS
Materials & surface treatments
Middle core
Segments
Retaining rings
Need other materials? Please consult!
Lifetime
Standard: applications of up to 500,000 cycles
DLC coating: designed for applications of up to 1 million cycles
Maximum working speed: 100 mm/sec
The DLC coating provides high hardness and a low coefficient of friction, helping to:
- Extend core service life
- Reduce resin adhesion
- Protect against corrosion caused by exhaust gases
- Recommended for high temperature molds
APPLICATION EXAMPLES
From automotive to medical technology
From automotive components to medical devices, electrical housings and consumer products, CUMSA collapsible cores enable the production of complex components with internal undercuts and intricate geometries across a wide range of industries.
Automotive · Electrical & Electronics · Food & Packaging · Medical Technology · Furniture · Sanitary & Plumbing · Fittings · Toys · Control & Regulation Systems
YOUR PROJECT
We love challenges!
Send us your project and we’ll find a way to make it real. Our technical team will get back to you, no strings attached.