Miniature Precision Components was losing hundreds of thousands of dollars in lost labor expenses, defective parts, and damaged equipment all because of inadequate cleaning methods.

For Miniature Precision Components, Inc. (MPC), meeting customer expectations and providing them with a quality product the “first time, on time and all the time” is the company’s mission. MPC is a supplier of functional thermoplastic injection assemblies and sub-assemblies for the automotive industry.

Its customers include General Motors, Chrysler, Ford, Harley Davidson, Nissan and Toyota. As a leading thermoplastic components and assemblies manufacturer, MPC manufactures millions of parts every year.

To produce such a large volume of parts, the company must keep its machines running. The MPS plant in Prairie du Chien, Wisconsin has 40 thermoplastic injection molding machines and a liquid silicone rubber (LSR) injection molding machine that uses a variety of materials and polymers.

Clean molds are essential

To ensure that the company meets its customer deadlines and high quality standards, the machines and molds must be maintained and cleaned regularly. After continuous use, the equipment becomes contaminated with degraded resin and gas residue. The press had to be shut down for the molds to be cleaned.

If not cleaned regularly and properly, the off-gassing and degraded plastic resin can build up in the vents and mold cavities, causing splays and burns. A rejected finished product could cost the company hundreds of thousands of dollars in lost labor expenses, defective parts and equipment damage. The molds are very expensive to replace, with one mold costing more than $80,000 while a small mold insert can cost up to $5,000.

“Our customers have come to expect nothing but high quality parts from MPC and given the competitive nature of the industry, they have no tolerance for defective parts. There is no margin for error, as replacing damaged equipment is expensive and a rejected part could cause MPC to lose the automotive customer.”

- Mike Wohlfarth, MPC Tooling Engineer

Traditional cleaning methods fall short

In the past, MPC used traditional cleaning methods like chemical solvents, ultrasonic, abrasives and Scotch Brite cleansers to rid the equipment of contaminants. These manual methods were extremely hazardous and posed serious safety concerns to employees. Maintenance crews were subjected to harmful chemical fumes and had to work closely between two halves of hot molds.

These cleaning methods were also time consuming, requiring a complete halt of the production line while the molds were disassembled. The cleaning chemicals sometimes damaged the equipment while the abrasives would remove steel on the parting line, causing flashing and resulting in a defective part. The Scotch Brite cleaning solutions could also damage the mold surfaces, removing the base metal and rounding the sharp mold edges.

MPC needed a cleaning solution that could streamline and improve its cleaning methods.

After evaluating its cleaning processes, the company identified the following requirements for a new cleaning system:

• Eliminate the risk of damage to its molds
• Reduce its dependency on chemical solvents
• Decrease labor costs
• Decrease preventive maintenance time
• Increase production time
• Clean molds online without exposing its employees to safety risks

Dry ice blasting met all requirements

After evaluating several cleaning solutions, the company turned to dry ice blasting.

Dry ice blasting is an industrial cleaning process that is similar in concept to sand blasting. Rather than using an abrasive media, dry ice cleaning uses recycled carbon dioxide (CO₂) in the form of dry ice pellets.

Dry ice blasting works by using compressed air to accelerate the dry ice pellets at supersonic speeds. It hits the mold surface creating numerous mini-explosions and sublimates on impact, leaving no secondary waste. The combination of the kinetic energy and thermal shock gradient of blasting with dry ice breaks the bond between the surface and the residue.

Learn more about how dry ice blasting works

MPC required a system that could not only clean efficiently but also manage the tight spaces and intricate details of its molds.  A dry ice MicroParticle system was ideal.    

For MPC, 1 - 1.5 blocks of dry ice provide between 45 to 60 minutes of continuous cleaning power, which can clean the entire backside of a mold, compared to the three to four hours it previously took with scrubbing. 

Learn about dry ice blasting for plastic applications

Dry ice blasting delivered results

1) 40% reduction in MPC's mold maintenance department, which has resulted in a more efficient and productive allocation of labor.

2) 50% reduction in mold maintenance costs due to the elimination of the abrasives damaging the molds.

3) Reduced press downtime

Because dry ice cleaning is a dry process and non-conductive, cleaning crews can clean the large vertical molds while they are still online, without the risk of damaging equipment or electrical components. The ability to clean online and at any time has increased cycles between scheduled preventive maintenance by 250%and reduced scheduled cleaning man hours by 81%.

4) Significant reduction in defect levels in end products

Cleaning with dry ice is also helping to extend the life of MPC’s tooling by facilitating thorough non-abrasive cleaning and reducing machine disassembly. Clean molds help to eliminate defects and ensure high quality end products.

“Our automotive customers have very stringent quality control procedures and demands and dry ice cleaning has helped us meet those part quality requirements."

- Mike Wohlfarth

5) Increased employee safety

The ability to clean with dry ice blasting while machines are still hot eliminates the need for employees to come into close contact with hot surfaces. The environmentally friendly dry ice blasting method is helping to reduce MPC’s dependency on harsh chemicals, creating a much safer working environment.

6) Return on investment in three months

The speed and efficiency of dry ice cleaning has allowed the company to reduce cleaning time by 75% and cut its cleaning crew by more than 60%. Because dry ice cleaning is a dry process and non-conductive, cleaning crews can clean the large vertical mold while they are still online, without the risk of damaging equipment or electrical components. 

“Just three precision dry ice cleaning systems are all we need to clean our entire fleet of molds and equipment. The process is quick, does not dull the tools and the portability of Cold Jet’s i3 MicroClean is a huge advantage as we can wheel it up to any machine in the plant for online cleaning. It has drastically improved our productivity and helped us cut costs. Simply put, dry ice cleaning is the best cleaning solution for our needs.”

- Mike Wohlfarth