“More time in mold repair is spent cleaning mold plates and tooling than in any of the other stages (disassembly, troubleshooting or assembly) combined.” - Steve Johnson of MoldMaking Technology.
That being the case, it makes sense to spend a little time reviewing your options. In this post, we will describe dry ice blasting, ultrasonic mold cleaning, laser mold cleaning and manual cleaning of plastic injection molds. We will also present the advantages and disadvantages of each method.
Dry Ice Blasting Unit
Figure 1 - Dry Ice Mold Cleaning System
The typical use of a dry ice mold cleaning system is to remove particles of plastic or rubber that stick to small pockets in the mold’s cavity. The operation is performed between two shots and repeated at regular intervals. It requires an operator and a large quantity of dry ice.
Advantages of Dry Ice Cleaning Systems
Can be used inline
Security measures are limited to adequate personal protective equipment (PPE) used by the operators
Disadvantage of Dry Ice Cleaning Systems
Require large upfront investments
Require considerable consumables (dry ice)
Dry ice has a limited shelf life, frequent reordering is required
Precaution must be taken when used in confined space due to CO2 buildup
Ultrasonic Cleaning Machine
Figure 2 - Ultrasonic Mold Cleaning System
Most ultrasonic cleaning of tools and equipments is carried out using water-based solvents, which are more environmentally friendly than the solvents required when cleaning molds by hand. The water solution is usually heated, which requires a lot of electricity.
it can take up a lot of space on your production floor. In addition, ultrasonic cleaning systems entail significant upfront investments and large operating cost. It makes these solutions less attractive to companies with a smaller number of molds to clean.
Typically, these machines are composed of a bath in which the parts to be cleaned are placed. There is a thermostat, timer, and a controller used to set the amplitude of the ultrasonic wave.
After 30 to 45 min the parts are ready and can be removed from the basin.
Advantages of Ultrasonic Mold Cleaner
Requires limited disassembly of the mold
Manipulation of the mold components is limited
Limited operator involvement
Disadvantages of Ultrasonic Mold Cleaner
Can only be used offline
Requires hot water and detergent
Laser Mold Cleaning
Using a properly developed laser cleaning system to remove rust, grease and any number of deposits is a better solution for many reasons.
First, a laser cleaning system requires no consumables, solvents or spray cleaners. From time to time, you might have to replace the filter for a dust and fume extraction device should you choose to use one.
Second, maintenance is limited to removing moisture and dust from the laser lenses as required. If you use Laserax Vortex, which is specifically designed to prevent the buildup of moisture stains and dust on the laser lens, you might never even have to clean the laser lens.
Third, laser mold cleaning processes can be automated and would not require any operator intervention.
Assisted Manual Laser Cleaning Solutions
Video 1 - Laserax Mobile Laser Cleaning System
Laserax has developed a mobile laser cleaning system that comes on a wheeled cabinet and is fully autonomous. All it needs is a regular 20 A electrical outlet. This laser system is equipped with an articulated assisted arm that ensures ergonomic handling of the laser head. This solution can be used either offline or inline to remove particles that tend to stick in areas of molds with small pockets.
Automated Laser Cleaning Solutions
Video 2 - Laserax Compilation of Laser Cleaning
Automated laser cleaning systems are also available. They consist of a laser, some enhancement options, and a laser safety enclosure. These systems are available either as standalone or as through-conveyor systems. In either configuration, the parts are cleaned using laser beams; the metal of the mold will not be affected as only the dirt, grease, oil, and other contaminants get vaporized.
Advantages of Laser Mold Cleaning
Laserax’s mobile laser cleaning system can be used either inline or offline
Requires no consumables
Only light maintenance
Long useful life (laser and optical apparatus have an MTBF of 100 000 h of continuous operations)
The use of laser systems using Class 1 laser safety enclosure requires no personal protective equipment (PPE)
Gives consistent repeatable results without adverse effect on the mold
Can be automated
Disadvantages of Laser Mold Cleaning
Large upfront cost
Class 4 mobile laser cleaning system requires extensive safety training, equipment, and procedures
Manual Mold Cleaning Method
Figure 3 - Manual Mold Cleaning 
Manually cleaning mold is a slow and tricky process. It involves the use of spray cleaners, solvents, and brushes. It requires a high-performance ventilation system or technicians might be exposed to fumes that are most likely to be detrimental to their health.
Manual cleaning methods require several mold manipulations to gain access to all sides of the tool. Manual cleaning can hardly take care of thick rust deposit. So most shops will increase the frequency of hand cleaning to ensure rust buildup that can be removed by hand.
Advantages of Manual Mold Cleaning
Low upfront cost, except for the ventilation system
Disadvantages of Manual Mold Cleaning
Important environment, health and safety (EH&S) management
Solvent disposal and recycling
Lots of manipulation of the mold
Requires a number of brushes, rags, and scrapers
Important risk of damaging the mold either because of the scoring or because of the handling of the mold
There are several options available for those that are willing to explore other ways of cleaning molds. Traditional cleaning methods, such as manual cleaning, ultrasonic cleaning and dry-ice blasting, offer many disadvantages that could lead to reduced productivity and mounting operating costs.
On the other hand, laser cleaning systems offer many benefits that might tip the competitive balance in favor of early adopters.
Laserax’s laser technology experts are at your disposal to help you better understand what the integration of a laser cleaner involves and how it might help your operation run smoother.
- Title Image "Analysis of Different Plastic Injection Mold Cleaning Solutions", is a derivative of “Shenzhen, Nov-2018” by Mitch Altman used under license CC BY-SA 2.0 "Analysis of Different Plastic Injection Mold Cleaning Solutions" is licensed under CC BY-SA 2.0 by Laserax Inc.