Zinc phosphate metal finishing line improves part turnaround time for precision machining company

Situation

A.R. Machining is a contract manufacturer in Hutto, Texas, specializing in precision machining work for the aerospace, oil, gas, and semiconductor industries. With more than 50 highly trained employees, a 38,000-sq.-ft. manufacturing facility, and more than 24 CNC mills and lathes with 4-axis capability, the company’s fast-turn prototype products include turnkey CNC production, part finishing, and mechanical assembly.

Original equipment manufacturers are demanding fast turnaround time from their suppliers to bring their products to market faster, and A.R. Machining’s customers are no exception. But without in-house finishing capability, the company was hampered. “Using outside finishers took several days and made it difficult to meet customer delivery requirements,” reported Matthew Dobias, president.

“Our oil and gas customers required corrosion-protected parts and just-in-time delivery,” Dobias continued. “These are large, down-hole steel components that often are stored outdoors before installation, so they are subject to corrosion. In our area, outside finishers are several hours away. Turnaround time was a real problem. Also, their finishing tank sizes were limited for our larger parts. We needed large capacity and ferrous metal corrosion protection.”

As part of its continuous improvement mission, the company decided to investigate in-house finishing options.

Resolution

“We knew about Birchwood Technologies and asked their area account manager, Tom Ingersoll, for metal finishing input,” said Dobias. “Birchwood Technologies chemists performed several no-obligation, no-cost test finishes on our sample parts in their lab. Tom recommended their zinc phosphate process and showed us how their MicroLok® MZN and Dri-Touch® Plus IRP3 process combination would answer our needs, so we went with a new system.”

This fine-grained zinc phosphating process is designed for iron and steel components, which make up the majority of A.R. Machining’s present work. Applied at 120 to 160 degrees F, the finish complies with MIL-DTL-16232G, Type Z Classes 1, 2, and 3—important because the company is expanding its work in the military sector. When sealed with a rust preventive, the finish has excellent corrosion resistance and provides antigalling protection and break-in lubricity to critical working surfaces, which are advantageous in certain military applications.

For extra corrosion protection, the Dri-Touch Plus IRP3 heavy-duty protective coating produces a robust film that is suitable for use on parts for limited outside storage, into warehouses, and for certain battlefield conditions. The product is an effective water displacer, with a self-healing, soft waxy film with thick consistency and high moisture resistance. “The combination process really improves the appearance of finished goods,” reported Dobias, “with parts coming out a nice, uniform dark gray or black depending on the material.”

The system comprises seven 220-gal.-capacity tanks with a 48- by 30- by 35-ft. footprint. An overhead crane is positioned above the system to handle large parts, which are up to 6 ft. long by 2 ft. in diameter, as well as baskets of smaller parts. The tank line is equipped with an adjacent ion exchange system, which purifies and recycles the system’s rinse waters. The result is a closed-loop system that conserves water and makes no discharge into the sewer system.

“With our new in-house system, we get same-day finishing. The cost is less than half compared to outside finishing and is improving as more work is added. Just as important, we eliminated many hidden costs using outside finishing vendors, such as the extra part moves, packing and repacking parts, inventorying and inspecting parts when received, and unexpected delays on different part projects,” Dobias added.