Sometimes, improving the quality of machined parts does not involve machining. That’s what A.R. Machining, a family-owned supplier to the aerospace, gas and semi-conductor industries, discovered. The Hutto, Texas-based prototype and production shop is committed to continuous improvement of its machining and finishing processes. Established in 1979, A.R. Machining has a full spectrum of CNC mills and lathes, ERP software, and quality assurance equipment, including CMMs. In addition to ferrous metal alloys, titanium, Inconel, aluminum and stainless steel, it also machines Teflon, Delrin, and PEEK. Its certifications include AS9100 Rev C, APIQ1, and ISO 9001.2015.
To improve product quality and turnaround time—including finishes on large steel downhole drilling components—A.R. Machining added a new zinc phosphate process from Birchwood Technologies, Eden Prairie, Minn.
“We needed both large capacity and ferrous metal corrosion protection,” said Mathew Dobias, president. “We asked Tom Ingersoll, our Birchwood Technologies area account manager, for metal finishing input.”
Birchwood Technologies offers a full line of finishes, including black oxide, aluminum oxide, zinc phosphate, antiquing, rust preventatives, and cleaners, as well as preps for finishes on iron, steel, stainless, aluminum, copper, brass, bronze, nickel and silver. Black oxide processes range from mid-temperature black oxide to room temperature black oxide.
“Chemists from Birchwood Technologies performed several no-cost test finishes on our sample parts in their lab,” said Dobias. “Tom recommended their MicroLok MZN and Dri-Touch Plus IRP3 processes, so we went with a new system.” The MicroLok MZN process is a fine-grained zinc phosphating solution for iron and steel components. These metals make up a majority of A.R. Machining’s current work. The MicroLok MZN zinc phosphate is a fine-grained gray finish that has a porous crystal structure to absorb a rust inhibitor topcoat. This finish is preferred for parts that do not require a black finish, but do require long-term corrosion resistance along with anti-galling properties or break-in lubricity.
Applied at 120-160°F (48.9-71.1°C), the MicroLok MZN finish complies with MIL-DTL-16232G, Type Z Classes 1, 2 and 3. When sealed with a rust preventive and with break-in lubricity to critical working surfaces, the finish produced important advantages for certain military applications. This was an important factor for A.R. Machining because the company is expanding its work in the military industry.
For jobs requiring extra corrosion protection, A.R. Machine utilizes Birchwood Technologies’ Dri-Touch Plus IRP3. It produces a robust film suitable for use on parts for limited outside storage, into warehouses, and for certain battlefield conditions. “The combination process really improves the appearance of finished goods,” said Dobias, “with parts coming out a nice, uniform dark gray or black, depending on the material.”
The Birchwood Technologies system that A.R. Machining installed consists of seven 220-gal (832.8-l) capacity tanks with a 48 × 30 × 35″ (1,219 × 762 × 889 mm) footprint. An overhead crane is positioned above the system to handle large individual parts and baskets of smaller parts. The tank line setup is equipped with an adjacent ion exchange system that purifies and recycles the system’s rinse waters.
“With our new in-house system, we get same day finishing,” said Dobias. “The cost is less than half compared to outside finishing. We eliminated extra part moves, packing and repacking parts, and inventorying and inspecting parts when received. Having in-house control of quality was a key consideration that led us to going with the new system. The fact that the process meets military specifications helps us acquire new work,” said Dobias.
According to Birchwood Technologies, typical MicroLok part applications include piston/cylinder assemblies, couplings, bushings and other components with sliding/mating surfaces. All of its processes can be used in-house, saving finishing costs and turnaround time to protect metal surfaces from corrosion, eliminate galling, and enhance sales appeal for tooling, firearms, military fasteners, gears, couplings, powdered metal, automotive hardware, and oil drilling components.
For more information from Birchwood Technologies go to www.birchwoodtechnologies.com, or phone 952-937-7931.
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