FAMILY 03 · SIBLING COMPONENT
3.1 Integrated Stator Overmolding
Direct high-adhesion polymer encapsulation molded onto customer-supplied or in-house sourced laminated silicon-steel stator cores.
Explore Stator Overmolding →Home › Products › 03 Insert & Stator Overmolding › Hollow Shafts w/ Internal Threads
Hollow Motor Shafts with Direct In-Mold Internal Threads & Splines
Complex hollow-core motor shafts featuring precision multi-start internal threads, helical grooves, or anti-rotation splines formed directly inside the injection mold via automated rotary-unscrewing core mechanisms. Requires zero secondary CNC tapping, eliminates thread burrs, and cuts component costs by 30%–50% compared to machined metal shafts.
✓ Direct In-Mold Rotary Unscrewing
✓ Zero Secondary CNC Tapping Required
✓ 30%–50% Metal-to-Plastic Cost Savings
PRECISION TOLERANCE
±0.02mm Thread Coaxiality
CORE POLYMERS
POM, PA66, PPS+GF, PEEK, PA46
SAFETY & COMPLIANCE
ISO 9001 / ISO 14001 · UL · RoHS/REACH
TOOLING & LEAD TIME
15–25 Days T1 · 7–10 Days Insert Swap
WHY ENGINEERS CHOOSE RUNHENG IN-MOLD THREADED SHAFTS
Seamless Internal Thread Accuracy Without Secondary Machining Costs
01. Automated Rotary-Unscrewing Mold Technology
Our in-house tooling center builds precision gear-driven and hydraulic rotary-unscrewing molds that form smooth, uninterrupted internal threads (metric, trapezoidal, or multi-start lead threads) in a single injection cycle.
02. Superior Strength vs. Post-Molded Tapping
Unlike CNC-tapped threads that cut across polymer flow lines and leave stress-concentrating micro-cracks, in-mold formed threads follow natural molecular orientation—delivering higher thread shear strength and zero loose swarf.
03. ±0.02mm Inner-Thread to Outer-OD Coaxiality
Forming the outer bearing journals, external splines, and internal threads simultaneously within one Charmilles EDM-machined cavity guarantees concentricity that secondary clamping can never match.
04. Lightweight & Self-Lubricating Operation
Molded in carbon-fiber/glass-fiber reinforced PPS, PA66, or PTFE-modified POM, reducing rotor inertia and eliminating metal-on-metal thread galling.
TECHNICAL SPECIFICATIONS
Hollow Shaft Internal Thread Engineering Parameters
Available Base Resins
Self-Lubricating POM, PTFE-Modified PA66, PPS+GF, PEEK, PA46 (DuPont / BASF Partners)
Supported Internal Features
Single/Multi-Start Lead Threads, Metric Threads, Helical Tracks, Internal Keyways & Splines
Coaxiality & Runout Tolerance
±0.02mm Between Internal Thread Pitch Cylinder and Outer Bearing Diameter
Molding Mechanism
Automated In-Mold Rotary Unscrewing & Collapsible Core Tooling (Zero parting line on threads)
Hybrid Overmolding Option
All-Plastic Hollow Shaft OR Internal Thread Overmolded Inside Metal Rotor Tube
Cost & Weight Reduction
30%–50% Unit Cost Savings & Up to 60% Weight Reduction vs. CNC Brass/Steel
Quality & Defect Control
≤ 50 PPM Defect Rate; 100% Thread Go/No-Go Gauge & Smooth-Travel Verification
Certifications
ISO 9001:2015, ISO 14001:2015, UL Process Certified, RoHS & REACH
STANDARD & CUSTOM CONFIGURATIONS
Supported Hollow Shaft & Internal Thread Configurations
Non-Captive Linear Motor Hollow Shafts
Hollow rotor shafts with precision internal lead-screw threads that drive linear shafts smoothly without external nuts.
Inquire Linear Hollow Shafts →
Metal-Tube Overmolded Internal Threads
Self-lubricating POM/PPS internal threads molded directly inside stainless steel or aluminum hollow motor shafts.
Request Custom Quote →
Dual-Spline & Threaded Actuator Sleeves
One-piece sleeves combining external anti-rotation splines with internal helical drive threads for compact valves and medical pumps.
Discuss Custom Unscrewing Mold →HOW WE GUARANTEE CONSISTENCY
How We Guarantee Thread Pitch Accuracy & Smooth Travel
01. Low-Friction & Low-Shrinkage Compounding
Custom PTFE/silicone-lubricated resins ensure consistent thread pitch shrinkage and low running torque.
02. Mirror-Ground Unscrewing Thread Cores
Threaded mold cores are precision-ground and polished so unscrewing extraction leaves a glass-smooth thread flank.
03. 100% Master Lead-Screw Travel & Runout QC
Every shaft is tested with calibrated master thread gauges for axial backlash, starting torque, and outer-diameter runout.
03 / INSERT MOLDING & STATOR OVERMOLDING FAMILY
Explore Other Metal-Insert Overmolded Components
FAMILY 03 · SIBLING COMPONENT
3.2 Overmolded Lead Screws & Shafts
Wear-resistant, self-lubricating engineering plastics molded directly onto stainless steel lead screws, motor rotor shafts, or brass guide cores.
Explore Overmolded Lead Screws →FAMILY 03 · SIBLING COMPONENT
3.3 Splined Brass Bushings & Linear Limiters
High-strength metal-plastic composite components combining splined brass or steel bushings with lightweight, vibration-damping engineering plastics.
Explore Bushings & Limiters →DIRECT ENGINEERING SUPPORT
Replacing CNC-Machined Threaded Shafts with In-Mold Forming?
Upload or email your 2D/3D component drawing (STEP, IGES, DWG, PDF) or share your component geometry. Free standard stock samples are available (freight collect), and custom DFM reviews are returned within 24 business hours.
✓ Free Standard Stock Samples (Freight Collect)
✓ 24-Hour Engineering DFM & Quote Response
✓ 100% NDA Confidentiality Protection
Send Your 2D/3D Drawing or Sample Request
Fill out the project specs below or attach your CAD files. Our engineering team responds within 24 business hours.
