Contract machinist automates high-accuracy prismatic machining

A bespoke robotic handling cell is now serving a DMG Mori five-axis vertical machining centre at the Redditch facility of Optimal Manufacturing, a contract machining company established in December 2022. Supplied by Whitehouse Machine Tools, the Tezmaksan CubeBOX installation is unusual in that the six-axis robot exchanges components fixtured in vices on pallets, rather than handling individual billets, castings or forgings.

Joint owners and directors Will Cooper and Tom Slimm opted for this approach because of the frequent requirement to hold tolerances below 10 microns. They concluded that the necessary repeatability was unachievable if the robot handled individual components, particularly when parts require a turnover operation between machining stages.

Instead, components sit securely in vices mounted on zero-point pallets, which locate into a pneumatically actuated clamping station on the table of a DMG Mori CMX 70 U machining centre, one of two five-axis machines at the site. The work holding and location equipment was supplied by Ceratizit.

Tezmaksan, the Turkish manufacturer of the robotic tending cell, performed significant modifications to its CubeBOX Blues DR MAX, one of the more heavy-duty plug-and-play systems in the range. The three storage shelves, which would normally be fixed and hold unclamped workpieces, were motorised so that they can slide horizontally towards the robot and retract again to allow manual loading and unloading. Each shelf stores four vice-mounted components. This modification was necessary because the relatively small spacing between shelves, compared with the nominal 300 mm cube envelope of the payload, would otherwise have prevented the robot gripper from accessing the lower levels.

The cell was commissioned in August 2025 and has since enabled Optimal to automate the production of high-precision prismatic components.

“It gives us unattended machining capability to match our bar-fed lathe, which already allows lights-out turn-milling of rotational parts up to 80 mm diameter,” says Will. “Shortly after Brown & Holmes Automation completed the turnkey installation on behalf of Whitehouse, we received a large order for stainless steel valve manifolds from an oil and gas customer. The job was ideal for automation and we ran the cell 24/7 for three months, including over Christmas, unattended every night. That allowed us to produce parts economically while maintaining short lead times.”

The choice of Tezmaksan was driven by flexibility, cost and the directors’ confidence in Whitehouse as a supplier. During their previous employment at an engineering firm in Birmingham, Whitehouse had supplied a Brother 30-taper machining centre that proved highly productive and well supported. After founding Optimal, the company also purchased a Taiwanese Leadwell 5-axis VMC with compound rotary table from Whitehouse in February 2024.

Six months after commissioning the automated cell, Optimal introduced additional flexibility for more open-tolerance work by allowing the loading of individual raw components directly on to the shelves. The company machine thin plates in-house for permanent mounting on each shelf. Large holes accommodate zero-point location, while a 50 mm hole grid enables the fixturing of multiple components — typically up to 36.

As with all CubeBOX installations, the system comes with Tezmaksan’s RoboCAM automation software, eliminating the need for third-party robot programming. New parts can be set up in two to three minutes, DXF files can be imported to automatically calculate grip points, and real-time tracking provides collision protection and production reporting.

Optimal supplies customers across the oil and gas, automotive, aerospace, and medical sectors, with batch sizes typically ranging from 20 to 50 components.

Tom concludes: “With long cycle times and 14 hours of overnight production effectively free, our priority is accuracy rather than marginal cycle-time reductions. This bespoke automation solution delivers exactly that.”