A new zinc phosphate finishing line proved to be a worthwhile investment for A. R. Machining (Hutto, TX). The line using Birchwood Technologies (Eden Prairie, MN) zinc phosphate process improved product quality and turnaround time, including finishes on very large, steel downhole drilling components.
A. R. Machining is a precision machining part supplier to the aerospace, gas and semi-conductor industries. As part of its continuous improvement mission, the company regularly upgrades its full spectrum of machining and finishing processes.
Choosing the Right Zinc Phosphate System
“We needed both large capacity and ferrous metal corrosion protection,” said Mathew Tobias, president of A. R. Machining. “We asked Tom Ingersol, our Birchwood Technologies area account manager, for metal finishing input. Birchwood Technologies chemists performed several, no-cost test finishes on our sample parts in their lab. Tom recommended their MicroLok MZN and Dri-Touch Plus IRP3 process, 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 the majority of A.R. Machining’s present work. Applied at 120 F to 160 F, the finish complies with MIL-DTL-16232G, Type Z Classes 1, 2 and 3. This was an important advantage for A. R. Machining because the company is expanding its work in the military industry. When sealed with a rust preventive, the MicroLok MZN finish has excellent corrosion-resistance and also provides anti-galling protection and break-in lubricity to critical working surfaces—important advantages in certain military applications.
For the needed extra corrosion protection, A. R. Machine uses Birchwood Technologies’ Dri-Touch Plus IRP3. It produces a robust film that is 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,” Dobias said, “with parts coming out a nice, uniform dark gray or black, depending on the material.”
The Birchwood Technologies system consists of seven 220-gal. capacity tanks with a 48 x 30 x 35 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,” Tobias said. “The cost is less than half compared to outside finishing. We eliminated extra part moves, packing, and repacking parts, 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.”