KCH Engineered Systems
Published

Using Alternatives in Pretreatment Baths for Degreasing

Effective cleaning at low, even ambient temperatures, is possible, says Atotech’s Brandon Lloyd, and creates a safer work environment and reduces energy demands.

Brandon Lloyd, Global Product Manager - Paint Pretreatment Technologies, Atotech

Share

Q: We have been using the same degreasing product for many years and it works relatively well for us, but it has a short bath life and operates around 150oF. After about a month, our parts are no longer cleaned effectively. What alternatives are available?

A: Properly cleaning a substrate surface is essential in achieving a high quality painted part. Without removing the soils (whether organic or inorganic), it is very difficult or impossible to form a desirable coating on the surface. The industry transition from phosphate conversion coatings to the more sustainable thin-film coatings (such as zirconium and silanes) have increased the importance of consistent substrate cleaning. Shortcomings in pretreatment quality contribute to costly paint defects and are a burden on operational efficiency.

Conventional cleaners, similar to yours, do typically operate at higher temperatures and tend to have a lower oil loading capacity. These cleaners provide adequate performance when new, but cleaning performance frequently decreases rapidly, resulting in a short bath life, increased defects and higher operational costs. With a shorter bath life, the frequency of new makeups increases, resulting in greater waste disposal or wastewater treatment costs. To maintain a system at higher operating temperatures, the amount of energy required is exponentially greater than a lower temperature process. To counter the low-oil capacity issues, auxiliary equipment can be implemented, which results in additional costs and maintenance.

New-generation cleaners are capable of resolving many deficiencies associated with conventional cleaners. Development and implementation of more sophisticated surfactant packages offer many benefits to applicators – most notably through extended bath life. Additional benefits include increased productivity, wastewater treatment and chemical savings, and improvement in part quality by maintaining stable performance over a longer duration. Effective cleaning at low temperatures, even ambient temperatures, is possible. This creates a safer work environment and reduces energy demands, resulting in improved operating costs.

Q: Some of our parts have welds and laser cuts which are frequently the culprit of many defects or rework. Currently, we ignore these areas because it is difficult to remove the scale formed during welding and laser cutting. Offering our customers a higher performing solution would allow us to expand our business. How can we achieve this?

A: Inorganic scales, such as the oxides formed during welding and laser cutting, impede the entire pretreatment process from operating optimally. Cleaning organic soils near the welds and laser cuts is often poor, and the formation of a conversion coating does not occur on the inorganic scales. For paints, inorganic scales pose several issues. The presence of scale impedes the paint from adhering to the base metal (much like conversion coatings), resulting in premature corrosion. Additionally, the silica inclusions formed during the welding process prohibit full coverage in ecoat applications, thereby increasing the possibility of premature corrosion. Some applicators attempt to resolve this by applying more paint on the parts, but this increases cost and does not always improve the impact resistance of the paint at the scaled areas.

Some applicators implement methods for removing weld and laser scale, such as acid pickles and mechanical means (media blasting, grinding), but there are significant disadvantages associated with each of those. Acid pickles pose a safety threat to employees, if not operated properly or with the appropriate precautions and personal protective equipment. They also have a short bath life as the scales build up in the solution, which then must be waste treated or shipped off-site for disposal. In considering media blasting, the removal of weld and laser scale can be effective in some applications. However, it can result in damage to the substrate surface, impregnate soils if dirty media is used and has line-of-sight issues for complex part geometries. Manual grinding also damages and alters the substrate surface, is not ideal for small components and is a significant hazard for operators.

Developments in chemical descaling technologies have increased in recent years, as applicators realize the safest and most cost-effective way to improve oxide removal is within the pretreatment sequence. Modern descaling chemistries offer much greater process versatility (operating in both immersion and spray applications); are free of many hazardous or regulated substances, such as phosphoric acid, fluoride, nonylphenol ethoxylates and hard chelating agents; and may even have built-in surfactant packages to support improved cleaning. Notable advancements include neutral pH descalers for improved employee safety and reduced equipment damage from exposure to corrosive acids.

Brandon Lloyd is global product manager for paint pretreatment technologies at Atotech. Stephen Taylor, North American product marketing manager, contributed. Visit Atotech.com.

Rectifiers for the Plating Industry
Reduced Ion Electroless Nickel
KCH Engineered Systems
FISCHERSCOPE® XAN® LIQUID ANALYZER
In-Place Repairs for Canning Presses
Hitachi High-Tech FT200 series
Luster-On Products
OptiCenter All-in-One OC11

Related Content

energy

Solar-Powered Photonic Cooling Enables Energy-Saving Coating

Passive cooling technology can reduce interior temperatures 5-13°C, offering weight, cost and CO2 benefits for cars, construction, aircraft and more.

Read More
energy

Portfolio of Energy-Curable Coatings Launched

PPG's DuraNEXT portfolio includes EB and UV curable coatings, offering rapid, energy-efficient solutions for metal coil coaters.

Read More
energy

One-Spray EV Battery Coating Provides Water Resistance and Chemicals

AkzoNobel's Resicoat launches one-spray powder coatings technology for EV battery systems, enhancing safety and productivity with high dielectric strength.

Read More
energy

NASF/AESF Foundation Research Project #123: Electrochemical Manufacturing for Energy Applications – 4th and 5th Quarter Report

The NASF-AESF Foundation Research Board selected a project on electrodeposition toward developing low-cost and scalable manufacturing processes for hydrogen fuel cells and electrolysis cells for clean transportation and distributed power applications.  During the reporting period, efforts were focused on planning the overall project work, with the eventual goal of manufacturing an improved design for a Solid oxide fuel cell anode supported flat tube (SOFC).

Read More

Read Next

workforce development

Education Bringing Cleaning to Machining

Debuting new speakers and cleaning technology content during this half-day workshop co-located with IMTS 2024.

Read More
sustainability

Episode 45: An Interview with Chandler Mancuso, MacDermid Envio Solutions

Chandler Mancuso, technical director with MacDermid Envio discusses updating your wastewater treatment system and implementing materials recycling solutions to increase efficiencies, control costs and reduce environmental impact.

Read More
Parts Cleaning

A ‘Clean’ Agenda Offers Unique Presentations in Chicago

The 2024 Parts Cleaning Conference, co-located with the International Manufacturing Technology Show, includes presentations by several speakers who are new to the conference and topics that have not been covered in past editions of this event.   

Read More
Fischer measurement technology