Case Study Injection Mold Cleaning - Sublimate Technologies

Injection Mold Cleaning for an Automotive Plastics Manufacturer

How in-press dry ice blasting eliminated mold disassembly, cut cleaning time by over 60%, and reduced scrap from contamination-related defects.

Key Results

60+

CLEANING TIME

Reduction vs. traditional method

Significant

SCRAP RATE

From contamination-related defects

Eliminated

MOLD DISASSEMBLY

Cleaned in-press at temperature

The Situation

A Central Indiana automotive plastics manufacturer operates a fleet of injection molding presses running high-volume interior trim components for OEM customers. The molds — multi-cavity tools with fine texture, tight vents, and complex parting line geometry — accumulate polymer residue, off-gassing deposits, and release agent buildup over thousands of cycles.

As contamination builds, the facility sees a predictable pattern: vent clogging leads to short shots and fill imbalance, parting line residue produces flash that requires secondary trimming, and surface deposits cause cosmetic defects on textured parts. Each defect mode adds scrap, rework, and inspection burden.

The Challenge

The facility’s existing mold cleaning process was manual and time-intensive:

Pull the mold from the press (crane time, setup labor)
Cool the mold to a safe handling temperature (1–2 hours)
Partially disassemble to access cavities, vents, and runners
Hand-scrape, wire-brush, and solvent-soak to remove buildup
Reassemble, reinstall, heat to operating temperature, and validate first shots

Total downtime per mold cleaning event: 6–8+ hours, depending on mold complexity. During this window, the press sits idle, production falls behind, and downstream assembly lines are affected.
The maintenance team also observed cumulative surface damage from wire brushing and scraping. Parting line surfaces showed wear marks, texture depth was decreasing in high-contact areas, and vent channels were widening — all contributing to shortened mold life and increasing tooling costs.

How We Work

1. Assessment and Custom Plan

We reviewed the mold designs, materials (P20 and H13 tool steel), surface textures, contamination types (polymer residue, off-gassing deposits, release agent accumulation), and the facility’s production schedule. A custom cleaning plan was developed specifying pressure settings, pellet feed rates, and nozzle configurations matched to each mold’s geometry and surface requirements.

2. In-Press Cleaning at Operating Temperature

The mold remained in the press at or near operating temperature. Dry ice blasting was performed through the operator-side access with the mold in the open position. Specialty nozzles were used to reach cavities, vents, runners, parting lines, and shut-off surfaces without removing any mold components.

3. Targeted Technique by Area

Different settings were used for different zones of the mold. Cavity surfaces with fine texture received lower pressure and finer media flow to clean without altering the texture. Vents, runners, and parting lines received higher-energy passes to clear stubborn carbon and polymer deposits. Core pins and lifter channels were cleaned with directional nozzles designed for tight geometry.

4. Containment and Documentation

Removed contaminant was captured using containment protocols. Before and after conditions were photographed for the facility’s maintenance records. Scope completion notes were provided for their ISO quality management system.

Cleaning Time: Reduced by Over 60%

The complete mold cleaning — both halves, all cavities, vents, runners, and parting lines — was completed in approximately 1.5–2.5 hours depending on the mold. Compared to the previous 6–8+ hour manual process (including pull, cool-down, disassembly, cleaning, reassembly, reinstall, and reheat), total downtime was reduced by over 60%.

Zero Mold Disassembly

The mold was never removed from the press. No crane time, no cool-down wait, no disassembly labor, no reassembly risk. The press returned to production immediately after cleaning and first-shot validation.

No Surface Damage

Parting line surfaces, textured cavities, vent channels, and polished areas showed no evidence of scratching, profiling, or dimensional change. The non-abrasive process eliminated the cumulative surface wear the facility had been experiencing from wire brushing and manual scraping.

Reduced Scrap

With cleaner vents, cleared runners, and restored parting line seal, the facility observed a measurable reduction in flash, short shots, and cosmetic surface defects in the cycles immediately following cleaning. Consistent cleaning intervals are expected to compound this improvement over time.

Production Value Recovered

By reducing press downtime per cleaning event by 4+ hours, the facility recovered significant production capacity. For a high-volume press running automotive interior components, even modest downtime reduction translates to meaningful output and revenue recovery over a production year.

Key Takeaways

Dry ice blasting cleaned complex injection molds in-press at operating temperature without disassembly

Cleaning time reduced by over 60% compared to the traditional pull-cool-scrape-reassemble process

Non-abrasive process eliminated cumulative mold surface damage from manual methods

Reduced flash, short shots, and cosmetic defects from contamination-related causes

Every job was custom-planned to match the specific mold geometry, material, and contamination type

Full documentation provided for the facility's ISO quality management records

Running injection molds that need cleaning without the downtime?

Contact us for a free mold cleaning assessment. We will evaluate your tooling, contamination, and production schedule and recommend a custom approach.