Automated Mill-Turn Cell From Brother Is Optimal for Subcontractor’s Unattended Production

Pete Wood, Operations Director at JWA CNC said, “Automation of lathes is easy using bar magazines and we have numerous such turning cells on our shop floor. However, autonomous production of milled components is more problematic because of the high diversity of shapes and small batch quantities.

“The typical selling price of prismatic parts going through our factory does not justify the purchase of a machining centre with a pallet storage and retrieval system, as they tend to be expensive and are also space-hungry. So robotic handling of the components themselves into and out of the machining area was a necessity.”

An early move towards this type of automation to compete with manufacturers in low-wage countries was made three years ago when the company decided to add a 6-axis cobot to a 4-axis BT40 machining centre on the shop floor. Operating with a single tray of parts, it works well unattended but has a couple of drawbacks. First, it is relatively slow to exchange a finish machined component for a new billet, taking around 3.5 minutes; and second, the automation takes up a lot of space.

In contrast, the Brother system avoids both of these negatives by executing component exchange in well under half a minute and by compressing the machining centre complete with its automation into a 3.5 metre x 4.1 metre footprint, only a little larger than that occupied by the cobot alone. With space at a premium at the Leicester facility, the compactness of the new cell is an important plus-point.

The integral robot effecting load/unload of the individual workpieces has four CNC axes, three rotational and one linear into and out of the

machine via an automatic door. It carries twin grippers with the end effectors opposed to each other at 180 degrees. They load and unload parts into and out of a pneumatically-actuated fixture on the rotary table mounted on a trunnion that swivels from +120 to -30 degrees. According to JWA CNC’s technical director Tim Shillabeer, the fact that a 4-axis rather than a 6-axis robot performs component transfer reduces set-up time and gives him confidence in a high level of ongoing operational reliability.

Three notable aspects of the Brother M200X3 are that it is the third BT30 machining centre in the factory but the first with a face-and-taper spindle; the second 5-axis model on site; and the only milling centre with a torque table capable of turning components in the same set-up. Several parts produced by JWA CNC require pre-turning before prismatic machining, so there will be a saving by performing both operations on the Brother, especially if the subsequent 5-axis milling and drilling allows parts to exit the machine in fewer set-ups, or perhaps even one.