1. Product Overview
We provide one-stop custom Injection Mold design & fabrication plus PP corrugated plastic sleeve injection molding service. The ribbed plastic sleeve as shown is integrally molded from virgin PP material, matched with tailor-made Injection Mold made of 738H pre-hardened mold steel with hardness HRC35~40. This single-cavity Injection Mold adopts pin-point gate feeding structure, and both core & cavity are fully high polished to guarantee flawless glossy part surface without burr or flow mark. All finished Injection Mold undergoes strict dimensional and surface inspection before delivery to support stable small-batch & prototype bulk production of corrugated plastic sleeves.
2. Technical Specification Table
| Item | Detailed Parameter |
| Molded Component | Corrugated Ribbed Plastic Sleeve with Mounting Ears |
| Molding Raw Material | Virgin PP Polypropylene |
| Mold Cavity Layout | 1×1 Single Independent Cavity |
| Core & Cavity Steel | 738H Pre-hardened Mold Steel |
| Steel Hardness | HRC 35~40 |
| Core & Cavity Finish | Double-sided Full High Polished Treatment |
| Gating System | Pin-point Small Point Gate |
| Cooperation Mode | OEM / ODM Custom Injection Mold + Custom Plastic Molding |
![1*1 PP Pin-point Gate 738H HRC35-40 Mold]( "1*1 PP Pin-point Gate 738H HRC35-40 Mold")
3. Core Advantages of Mold & PP Sleeve
✅ Stable 738H HRC35-40 Injection Mold Performance
738H pre-hardened steel features excellent cutting performance, uniform hardness at HRC35-40 and outstanding polishing property. No extra heat treatment required after machining to shorten mold lead time, ideal for polished core/cavity processing and medium-cycle continuous PP injection molding.
✅ Full Polished Core & Cavity Design
Both mold core and cavity are precision high polished, effectively eliminate sink mark, flow line and surface scratch on the corrugated rib surface of plastic sleeve; reduce post-finishing work and lower product reject ratio.
✅ Precise Pin-point Gate Structure
Small pin-point gate leaves tiny invisible gate mark on product surface after ejection, no manual gate trimming needed; ensure neat appearance on sleeve’s mounting ear position, well protect the precision structure of mounting holes and side buckle lugs.
✅ Practical Corrugated PP Sleeve Structure
Outer annular ribbed corrugation improves part flexibility, shock absorption and bending resistance; top mounting ears with two fixing holes realize easy screw installation, bottom notch for quick snap-fit assembly. Virgin PP brings good chemical resistance and dimensional stability for long-term usage.
✅ Flexible 1*1 Single Cavity Customization
Single cavity mold is perfect for new product trial sample development and small customized batches; we adjust sleeve diameter, rib spacing, mounting hole size and notch dimension per clients’ 2D/3D drawings or samples.
4. Main Application Fields
Household appliance motor shaft dustproof flexible sleeve
Automotive small wiring harness corrugated protective bushing
Pneumatic equipment pipeline buffer protection cover
Electronic device internal plastic fixing & insulating sleeve
5. Standard Custom Service Workflow
Client provides 3D drawing or physical sleeve sample →2. DFM feasibility analysis & Injection Mold structural design →3. CNC precision machining + full polishing for 738H core and cavity →4. Pin-point gate system processing & mold assembly →5. Virgin PP trial injection and sample confirmation →6. Mass custom molding after customer sample approval
FAQ Section
Q1: How many molding shots can this 738H Injection Mold reach?
A: With regular daily maintenance, the HRC35-40 738H Injection Mold can steadily achieve over 400,000 shots for PP corrugated sleeve production.
Q2: Can you revise rib pitch or mounting hole size on finished Injection Mold?
A: Our in-house mold workshop can modify core insert to adjust sleeve structure parameters as updated technical drawings.
Q3: Can customers get pre-production trial samples before bulk molding?
A: Yes, we arrange PP prototype samples after mold completion for your dimension and appearance inspection.
Q4: Can this Injection Mold switch to HDPE/TPE raw material?
A: After fine-tuning injection parameters, this mold supports HDPE or flexible TPE sleeve molding upon our technical assessment.
