Seal the deal: Turning Performance

Versa-Fab Inc., New Kensington, Pa., is a busy fabrication, machining and finishing business. The company serves a variety of customers while emphasizing the manufacture of sheet and stainless steel cabinets for the power products and distribution industry.

Vice President James Cullen said the business may appear simple, but “we put through 700 different part numbers and manufacture and ship more than 20,000 parts in a month.” As a result, the company is constantly looking at where it can employ flexible automation to generate efficiency.

Courtesy of Versa-Fab

Versa-Fab combined bar-fed lathe operations and vertical milling to machine this 1 “-long, 316 stainless steel gas hose seal in a cost-competitive way.

Versa-Fab’s machine shop supports the company’s fabrication operations and makes parts for external customers. “We are a very robust job shop,” said Matt Aubele, machine shop manager. Successfully bidding on outside jobs requires the shop to be cost-competitive. Aubele said one job symbolizes the company’s efforts to automate whenever possible. That part is a 1⁷⁄₈ “-long, 316 stainless steel gas hose seal. It has a maximum diameter of 2³⁄₈ “, a 1-14 UNS thread, two grooves for O-ring seals and connects a gas hose to a tank.

Although the part would be well-suited for a live-tooling machine with a Y-axis and C-axis, the shop did not have that kind of equipment when bidding the job. “We had to figure out a way to be competitive,” Aubele said.

They did. Versa Fab efficiently processed the part by combining a bar-fed SL20 Haas lathe with a Haas VF3 vertical machining center.

Working with a part print, Aubele programmed the job in Mastercam. Versa-Fab machines the seal from 2 ³⁄₈ “-dia. bar stock, which is sawed into 3 ‘ lengths and loaded into the SL20’s bar feeder. The first operation is turning the bar’s diameter to 2.142 “, then stepping in to turn the 1 ” major diameter of the thread, using Iscar CNMG-432 inserts run with flood coolant at a 600-sfm cutting speed and a 0.008-ipr feed rate.

To machine the 0.088 “-deep × 0.051 “-wide O-ring groove on the front of the part, the shop chose an Iscar Picco 0.030 “-wide, solid-carbide face-grooving tool. The shop only runs the tool at 200 to 300 sfm and 0.001 ipr. “We’ve always run it very conservatively because it is on a bar-fed machine and there is no one standing there,” Aubele said. “When I started in this business as a programmer, I always wanted to push a tool as hard as it would go. I have learned it’s not always the best to push it so hard. Slow and steady isn’t hurting anything because the machine is just running by itself.”

Next, the 1-14 UNS thread is cut with six passes of a Vardex single-point threading tool. After that, a 12.7mm-dia. Guhring P/M drill run at 340 sfm and 0.0065 ipr drills a 1 “-deep hole in the center of the seal. When the seal is parted off with an Iscar 0.118 “-wide, TAG-style cutoff tool, a 0.256 “-wide flange remains on the back of the part.