Technical Brief: Collapsible Core Moulding
The Problem
Manufacturing parts with internal threads or undercuts is usually slow and expensive. Traditional methods (like unscrewing tools) cause:
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Long Delays: 50-second cycle times.
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High Costs: Tooling costs around $1,200.
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Maintenance: Frequent breakdowns and manual finishing work.
The Solution: Collapsible Core
We use a core that expands to mould the thread and collapses inward to release the part. This removes the need for complex unscrewing parts.
Why it works better:
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Faster Production: Cycle time dropped to 30 seconds (35% faster).
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Cheaper Tooling: Cost reduced to $450 (62% savings).
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Better Quality: No part deformation or scratches.
Quick Comparison
| Feature | Old Method | Manufyn Solution |
| Cycle Time | 50 Seconds | 30 Seconds |
| Tooling Cost | $1,200 | $450 |
| Manual Work | High | Zero |
| Tool Life | Short | Long (0.1M+ parts |
Collapsible Core Injection Moulding: Internal Undercut + Cost Reduction
How Manufyn reduced tooling cost by 62% and cycle time by ~35% for a global OEM
Who This Solution Is For
This collapsible core injection moulding solution is ideal for:
- OEMs and industrial product companies
- High-volume plastic component manufacturing
- Parts with internal threads, undercuts, or complex ID geometry
- Projects requiring automation, fast cycle time & consistent tolerance control
Client Overview
A global OEM approached Manufyn to manufacture a plastic component with an internal undercut and threaded profile. The part was used in a high-volume assembly for industrial equipment, where performance, repeatability, and dimensional stability were critical. However, the OEM’s previous attempts resulted in slow cycles, tooling failures, and inconsistent tolerances, which made scaling difficult.
The Challenge
Traditional moulding methods like side cores and unscrewing systems produced the part but introduced:
- Cycle time of 45–50 seconds
- High tooling complexity & frequent breakdowns
- Dimensional variation in the undercut area
- Additional finishing and secondary operations
Moreover, a straight-pull tool was not feasible due to the internal ID undercut, which physically locked the part inside the mould during ejection.
Challenge Summary:
Mould a threaded internal undercut with zero manual intervention, reduced maintenance, consistent results, and commercially viable production costs.
Manufyn’s Engineering Solution
Manufyn engineered a collapsible core injection moulding tool. During injection, the core expands to create the internal thread and undercut. After cooling, it collapses inward, freeing the part without distortion. This eliminated unscrewing mechanisms and multi-slide side actions, creating a cleaner, faster, and more reliable production cycle.
Key Solution Features
- Fully automated moulding cycle
- No side actions or unscrewing mechanisms required
- Smooth part release with zero deformation
- Longer tool life due to reduced wear points
- Controlled thread accuracy and surface finish
Technical Specifications
| Parameter | Value |
|---|---|
| Outer Diameter | 5 inch |
| Inner Diameter | 3 inch |
| Wall Thickness | 0.5 inch |
| Tooling Mechanism | Collapsible Core |
| Production Volume | ~0.1 million parts / tool |
Manufacturing Process
The collapsible core injection moulding process was designed to ensure dimensional stability, repeatability, and automation. Here’s how the production sequence works:
1. Before Injection
- Collapsible core segments are aligned and tensioned
- Mould base, cavity plates & channels are stabilized
- Concentricity between ID & OD is verified
This ensures:
- Zero axial movement
- Clean undercut formation
- Consistent expansion every cycle
2. During Injection
As the mould closes, the core expands and locks into geometry. Molten plastic flows into the cavity with controlled temperature and pressure, filling:
- Undercut regions
- Threaded surfaces
- Sharp internal corners
Material flow control ensures:
- Proper cavity packing
- No sink marks
- Uniform wall thickness
3. After Cooling
Cooling stabilizes the geometry and thread profile, preventing collapse-induced distortion. Once stabilized:
- The core contracts inward
- The part is released without friction or stretch
- The standard ejector system removes the part cleanly
This stage prevents dragging, surface scratches, or deformation — which is why no secondary finishing is required. The part exits the mould assembly-ready.
Results & Performance Improvement
| Performance Parameter | Conventional Method | Manufyn’s Collapsible Core |
|---|---|---|
| Cycle Time | 45–50 sec | 28–30 sec (~35% improvement) |
| Tool Complexity | High | Optimized / Medium |
| Maintenance | Frequent | Low |
| Dimensional Consistency | Variable | High / Repeatable |
| Secondary Operations | Required | Eliminated |
| Production Efficiency | Standard | Higher output per shift |
Additional Benefits
- Reduced risk of tool failure and downtime
- Cleaner internal threads and improved surface finish
- Improved scalability for high-volume manufacturing
With performance validated, the commercial impact became much clearer.
Commercial Impact
| Cost Area | Previous Vendor | Manufyn |
|---|---|---|
| Tooling Cost | $1200 | $450 (62% lower) |
| Per Tool Life | Unspecified | ~0.1 million parts |
| Secondary Costs | High | Almost Zero |
For similar injection moulding assemblies, Manufyn offers tooling costs starting from $200, depending on size and complexity.
Why Manufyn
- End-to-end manufacturing: CNC, injection moulding, extrusion
- DFM + feasibility review before tooling investment
- Faster cycle time & automation-first production approach
- Engineering + commercial balance for ROI-focused manufacturing
How to Start With Manufyn
Getting started is simple and structured:
| Step | What You Do | What We Deliver |
|---|---|---|
| 1. Share CAD / Drawing | Email or upload file | NDA + DFM review |
| 2. Feasibility Evaluation | Requirements discussion | Tooling approach + quote |
| 3. Prototype / T1 Samples | Approval and testing | Validation report |
| 4. Production Run | Place order | High-volume supply with QC |
Entry Options
Upload drawing for feasibility check
Request prototype / T1 quote
Share volumes for cost/per-part optimization
Conclusion
Manufyn’s collapsible core injection moulding approach enabled the OEM to:
- Reduce cycle time by ~35%
- Remove secondary operations entirely
- Improve dimensional accuracy & surface finish
- Cut tooling cost by 62% and scale production confidently
This case proves how the right tooling design can deliver both engineering precision and commercial advantage.
Ready to manufacture components with internal undercuts or threaded profiles?
Share your drawing or CAD file for a feasibility check — no obligation.
