INDUSTRY COMPONENT

Guide Bore

Precision-machined cylindrical bore in ejector housings that guides ejector pins during injection molding cycles.

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Component Specifications

Definition
A guide bore is a precisely machined cylindrical cavity within an ejector housing component of injection molding machines, designed to maintain strict alignment and smooth linear motion of ejector pins during the ejection phase of the molding cycle. It ensures consistent part release by preventing pin deflection, binding, or misalignment that could damage molded parts or the mold itself.
Working Principle
The guide bore operates on the principle of constrained linear motion, providing a hardened, low-friction surface that restricts ejector pin movement to a single axis. During ejection, hydraulic or mechanical force drives the ejector plate forward, pushing pins through these bores to contact and dislodge molded parts from the cavity. The bore's precise diameter and surface finish minimize clearance while allowing smooth sliding, ensuring pins return accurately to their retracted positions.
Materials
Typically made from hardened tool steels (e.g., AISI D2, H13, or S7) or carbide inserts for wear resistance. Surface treatments like nitriding, chrome plating, or TiN coating may be applied to reduce friction and extend service life. Hardness ranges from 48-62 HRC depending on application demands.
Technical Parameters
  • Depth Varies by mold design (typically 50-200 mm)
  • Straightness 0.01 mm per 100 mm
  • Concentricity Within 0.01 mm relative to mating features
  • Surface Finish Ra 0.4 μm or better
  • Diameter Tolerance ±0.005 mm
Standards
ISO 286-2, DIN 7154

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Guide Bore.

guide bore ejector housing injection molding ejector pin alignment precision machining tool steel components mold maintenance linear bearing surfaces Guide Bore in Machinery and Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Ejector Housing

The structural enclosure that houses and protects the ejector mechanism in an ejection system.

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Engineering Analysis

Risks & Mitigation
  • Misalignment causing part defects
  • Wear leading to increased clearance and flash
  • Corrosion in humid environments
  • Thermal expansion mismatches
FMEA Triads
Trigger: Inadequate lubrication or contamination
Failure: Accelerated abrasive wear and scoring
Mitigation: Implement regular cleaning and use high-temperature, mold-safe lubricants; install protective seals
Trigger: Material fatigue from cyclic loading
Failure: Cracking or deformation of the bore
Mitigation: Use fatigue-resistant steels (e.g., H13), ensure proper heat treatment, and avoid over-tightening during assembly
Trigger: Improper installation or misalignment
Failure: Binding or uneven wear of pins and bores
Mitigation: Follow precise alignment procedures during mold assembly; use jigs and verify concentricity with dial indicators

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Meets ISO 286-2 for cylindrical fits (e.g., H7/g6 clearance fit)
Test Method
Dimensional verification with bore gauges or CMM; surface roughness testing per ISO 4287; hardness testing per ISO 6508

Buyer Feedback

★★★★☆ 4.9 / 5.0 (20 reviews)

"The technical documentation for this Guide Bore is very thorough, especially regarding technical reliability."

"Reliable performance in harsh Machinery and Equipment Manufacturing environments. No issues with the Guide Bore so far."

"Testing the Guide Bore now; the technical reliability results are within 1% of the laboratory datasheet."

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Frequently Asked Questions

What happens if a guide bore wears out prematurely?

Premature wear can cause ejector pin misalignment, leading to part damage, flashing, or mold scoring. It increases downtime for repairs and may require re-machining or replacement of the housing.

How often should guide bores be inspected?

Inspect during regular mold maintenance cycles (every 50,000-100,000 cycles for high-volume production). Check for scoring, diameter enlargement, or loss of surface finish using bore gauges and visual inspection.

Can worn guide bores be repaired?

Yes, through re-machining to a larger diameter and fitting with bushings or sleeves, though this may require matching ejector pin replacements. Severe damage often necessitates full housing replacement.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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