Dry Ice Blasting: Cleaner Molds. Less Downtime. 

Dry ice blasting cleans injection molds faster, safer, and with less downtime than traditional methods — here's how it works and why it's the preferred choice for plastic and rubber manufacturers.

In the plastics and rubber industries, product rejection and poor part quality are detrimental to manufacturers. In injection molding, there is no margin for error. Every part must come out perfect, with tolerances measured in thousandths of an inch.

A dirty injection mold is the usual suspect when quality falls, causing issues that range from warped products to texture imperfections. No matter how small the defect is, it can potentially affect thousands of units, increasing scrap and costs when trying to meet production quotas.

Why Are Dirty Injection Molds a Problem?

Injection molds used in the production of plastic, rubber, and other synthetic parts are some of the most expensive and sensitive assets any factory owns. Often made from industrial-grade steel and machined into very specific shapes, these molds can have varying geometries. Additionally, these molds are often polished and are sensitive to scratches and other damage.

As these molds are continuously used day in and day out, residue builds up in the form of the following:

• Resin buildup and offgassing
• Mold release agents
• Carbon deposits
• Factory dust
• Oil and grease

Beyond the primary cavity surfaces, the microscopic parting-line vents become severely restricted by off-gassing and residue. Left unaddressed, this progressive vent fouling traps volatiles that lead to dieseling (burn marks), short shots, and ultimately, an unacceptable spike in scrap rates.

Why is Cleaning Injection Molds Critical?

Injection molds must be cleaned regularly to avoid poor mold performance and low OEE scores. Production managers are always striving to accomplish the following:

• Increased productivity (i.e., less downtime due to cleaning or malfunction)
• Higher quality products (i.e., less contaminants in the mold that alter integrity)
• Reduced costs (i.e., less scrap created from imperfect products, less labor needed)

A small issue duplicated repeatedly can spell disaster for any manufacturer and must be avoided at all costs.

Why Are Traditional Cleaning Methods Ineffective with Injection Molds?

Unfortunately, too many factory floors are reactive to contamination buildup instead of proactive. Too often, molds do not get cleaned until the buildup becomes a problem for production rather than regularly cleaning the molds.

A traditional cleaning session would include:

• Taking the press offline
• Waiting hours for the tool to cool down
• Disassembling the tool
• Hours of labor-intensive and abrasive cleaning

The obvious problem with using such abrasive cleaning methods is their potential for damaging the high-value injection molds, where even the smallest chip, scratch, or scrape can affect part quality. Chemical-based cleaners can also strip the outer layers of the mold over time, shortening its service life.

Injection molds are very expensive to produce and replace, and damaged ones can ruin whole batches of products if they go unnoticed. With so much on the line, what can a factory do to keep its injection molds cleaner for longer and boost productivity while also reducing downtime?

Dry ice blasting is the answer for keeping injection molds working at optimum capacity.

How Does Dry Ice Blasting Efficiently Clean Injection Molds?

Due to dry ice’s special properties, it marries the need for constant cleaning with a solution that can remove contamination without stopping production. Unlike other industrial cleaning methods that require shutdown and disassembly, dry ice blasting does not, and contributes the following benefits:

Non-abrasive:

Above all other things, a maintenance technician does NOT want to damage the injection mold or any of its intricate grooves, cavities, or surfaces. Dry ice removes contaminants with ease through kinetic impact, thermal shock, and rapid expansion. These factors, coupled with the fact that dry ice is about a 1.5 out of 10 on the Mohs Hardness Scale, make dry ice ideal for cleaning mold surfaces that have intricate geometries and textures without damage.

Non-conductive:

Particularly useful when cleaning electrical components and water-sensitive parts, dry ice does not conduct electricity. Wires, connections, and other electronic components of injection molding machinery that must stay dry are safe since dry ice is water-free and chemical-free.

No secondary waste:

After breaking the grit’s bond from the surface of the mold, the dry ice pellets sublimate into CO₂ gas immediately. When the cleaning is done, there is no toxic debris, wastewater, or newly created contaminant to clean up afterwards. Thousands of dollars and hours of time can be saved from not dealing with extra waste alone.

Fast and efficient:

Dry ice blasting works FAST. All the steps listed above happen in an instant, leaving contaminant-free surfaces and cavities behind, often after only one pass over the area with the blasting nozzle. Additionally, injection molding machines do not need to be shut down, cooled down, or removed from the press to be cleaned. Dry ice blasting can remove contaminants without significantly affecting surface temperatures, and the machines can resume production with little downtime between cycles.

Cleans hard-to-reach places:

Some traditional cleaning methods often leave crevices and tight spaces untouched. Dry ice pellets blasted at high velocity can fit into the smallest of spaces to deliver their cleaning power, especially when coupled with special hooked nozzles designed for cleaning tight spaces.

What Are the Steps for Cleaning Injection Molds with Dry Ice Blasting?

1. Evaluate contaminant type and saturation

Knowing what kind of grit, dirt, or contaminant you are trying to remove is just as critical as knowing the level of contamination present. Understanding both factors plays a significant role in choosing your dry ice pellet size, blasting pressure, consumption rate, and other dry ice blaster settings for successful cleaning.

2. Evaluate substrate material and surface texture

While most injection molds will be made of industrial-grade polished steel, there may be other mold variants used that may require additional assessment for temperature or blasting media tolerances. Additionally, uneven or carved textures should be evaluated for any hard-to-reach spots and blasting sensitivities.

3. Choose dry ice blaster settings to fit the contaminant type, consistency, and substrate being cleaned

Here are some key things to remember when choosing your dry ice blasting settings:

• Harder, thicker, and more stuck-on contaminants typically need a larger pellet size and higher pressure to break up the contaminant from the substrate
• Delicate surfaces with sensitive geometries and textures should use smaller pellet sizes and lower pressures to adequately clean hard-to-reach places, crevices, cavities, and grooves
• Choose a nozzle type that suits the surface you are cleaning and offers variability to clean various surface types in a single cleaning session when possible; ensure the nozzle can also clean the hard-to-reach spots as well

4. Clean critical areas for injection molding machines functionality

When cleaning with dry ice, ensure you are targeting the following areas:

• Cavities and cores
• Vent channels
• Ejector pin locations
• Parting lines
• Slides and lifters

Should Dry Ice Blasting Be Part of a Regular Injection Mold Maintenance Program?

To keep injection molds working at their best all day, every day—plant and factory managers should incorporate dry ice blasting into a regular cleaning schedule as an effective preventative maintenance measure. Because dry ice blasting requires no disassembly and doesn’t take machines offline, cleanings can easily take place between production runs — adding minimal disruption while keeping molds in peak condition.

Reactionary cleaning can lead to problems, so making dry ice blasting a routine part of the process will ensure the following:

• Longer production runs with less downtime
• Longer-lasting mold lifespans to cut costs
• Less scrapped products due to imperfections

Final Takeaway: Dry Ice Blasting Outperforms Traditional Mold Cleaning Methods

Dry ice blasting is one of the most effective methods available for keeping injection molds clean, performing reliably across mold types, surface finishes, and contaminant levels. When it comes to keeping injection molds clean and production on track, speed and precision matter. With dry ice blasting, molds do not need to be taken offline. They can stay hot and in place as a maintenance technician removes buildup between production runs, allowing operations to resume much faster — often by 50% or more — than with traditional mold cleaning methods.

Are you ready to keep your facility productive without letting dirty injection molds hold you back?

Contact Cold Jet to find the right dry ice blasting solution to keep production going!