Elastomer პროგრამების სპეციალისტი
1998 წლიდან NVH– ს საუკეთესო გადაწყვეტილებები
Chinese rubber parts factory

სიახლეები

Technical Analysis and Improvement Plan for Mold Sticking and Air-Trapping Issues in Rubber Processing

Posted on15 December 2025

In rubber manufacturing, both vulcanized rubber parts and non-vulcanized rubber parts commonly face technical chყველაenges such as mold sticking, roller sticking, and air bubbles.

The following is a complete საქმე analysis and systematic improvement plan, applicable to rubber rollers, rubber sheets, seals, and most general rubber პროდუქტები.



1. Background: Material Changes Causing Severe Mold Sticking & Air Bubbles

After raw material adjustments, the პროდუქტიion experienced severe mold sticking, trapped air, and unstable processing:

Reclaimed rubber: low rubber შინაარსი → high rubber შინაარსი (viscosity increased)

Rubber powder: coarse powder (10 mesh) → fine powder (40 mesh)

Result: higher toughness, tighter bonding, significantly reduced venting performance

Original Formula

NR: 4 kg

SBR: 4 kg

Reclaimed rubber: 19 kg

Rubber powder: 6 kg

The წინა formula (cheap reclaimed rubber + coarse powder) had no mold sticking issues, but after upgrading materials, the problem amplified significantly — a common situation during vulcanized rubber part პროდუქტიion.


2. Technical Cause Analysis: Why Mold Sticking and Air Bubbles Occurred

1) Increased intrinsic tackiness of materials

Higher-rubber-შინაარსი reclaimed rubber behaves closer to virgin rubber →
More active molecular structure → Significantly higher mold adhesion.

2) Rubber powder changed from coarse (10 mesh) to fine (40 mesh)

Fine powder binds more tightly into the compound:

Higher cohesion

More compact structure

Much poorer air release → severe air trapping

3) Compound became overly dense and tight

Dense compounds easily cause air traps, scorching, and sticking during vulcanization.


3. Feasible Improvement Measures (Field-Verified Results)

გადაწყვეტა 1: Increase ratio of coarse rubber powder (improve venting)

From 50 phr → 100 phr

Result: Air bubble rate improved from 100% → 30%.
Coarse powder loosens the compound structure, improving air escape — especiყველაy helpful for non-vulcanized processing.


გადაწყვეტა 2: Use mold release agent (critical step)

The factory წინაly used no release agent at ყველა (high-risk practice).

After applying release agent:
Bubble rate: 30% → 15%

Release agents are standard for producing vulcanized rubber parts.


გადაწყვეტა 3: Mold surface treatment (key factor)

Original mold: no plating / no PTFE / no polishing → extremely prone to sticking.

რეკომენდირებული treatments:

PTFE (Teflon) coating

Chromium plating

Polishing to low surface roughness

Smoother molds = dramaticყველაy less sticking.


გადაწყვეტა 4: Adjust compound looseness

If the compound is too sticky/dense:

Increase stearic acid / paraffin (your 2.5 / 1.5 phr is normal but can be adjusted)

Add large-pსტატია fillers to open the structure

Reduce density by increasing coarse rubber powder

Your final changes (adding 80 phr coarse powder + release agent)
→ Fully resolved mold sticking issue.


4. Four Core Causes of Mold Sticking (Summary)

This საქმე had four simultaneous issues, which is why sticking was so severe:

Material tackiness increased significantly

Mold had no surface treatment

No release agent used during პროდუქტიion

Compound became too dense → poor venting

When several of these occur together, mold sticking in vulcanized rubber parts becomes inevitable.


5. Final Recommendations (Applicable to ყველა Rubber Factories)

1. Perform proper mold surface treatment

PTFE coating

Chromium plating

Regular cleaning & polishing

2. Use release agent for every batch

Especiყველაy critical for vulcanized rubber parts.

3. Adjust compound consistency when tackiness is too high

Increase fatty acids / wax

Add coarse powder to reduce density

Introduce large-pსტატია fillers if needed

4. Looser compounds = better venting

This is essential for molds with deep grooves or poor vent paths.

Technical Analysis and Improvement Plan for Mold Sticking and Air-Trapping Issues in Rubber Processing

In rubber manufacturing, both vulcanized rubber parts and non-vulcanized rubber parts commonly face technical chყველაenges such as mold stickingroller sticking, and air bubbles.

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