Hydraulic Projects (Hy-Pro), the Dawlish-based manufacturer of hydraulic control valves, pumps and marine steering systems, has expanded its production capacity significantly in the last decade.
Employing 40 staff and serving a global customer base, the company produces 85% of its components in-house from aluminium billets and iron castings. To raise even further the efficiency of its machine shop to help feed the assembly lines with an increasing number of components during a recent upturn in business, Hy-Pro turned again to workholding specialist
1st Machine Tool Accessories (1st MTA).
The clamping equipment supplier initially delivered a US-made Chick Multi-LOK tooling column in 2016 for use on an
Okuma horizontal machining centre, equipped with a 218-tool magazine and a 10-pallet pool.
1st MTA has supported the manufacturer’s growth ever since, in particular following the installation in Dawlish in March 2021 of a second, nearly identical Okuma flexible manufacturing cell. As a consequence, there are now six Chick Multi-LOKs in use across the factory.
They enable dozens or even hundreds of parts to be set up in each Okuma cell to enable machining 24 hours a day, six days a week, including lights-out overnight.
Pic: Paul Vicarage, quality engineering manager Hy-Pro, demonstrates the ease with which a Chick QwikChange faceplate can be removed from a Multi-LOK tooling columnIn both cells, workpiece setup is carried out off-line at a load/unload station in the pallet pool guarding, so the spindle waits only for as long as it takes to deliver a pallet to the machine and rotate it into the working area.
Paul Vicarage, quality engineering manager at Hy-Pro, highlighted the impact of this: "We are getting about six 24-hour days’ worth of machining for about four and a half days of single-shift operator input. Moreover, we benefit from high spindle uptime and considerable operational flexibility."
To maintain secure workholding across various component types, Hy-Pro stores on-site about 20 compact, multi-part fixtures for attaching to the four sides of its tooling columns. Each fixture has a set of soft jaws machined in-house, or other workholding equipment, to suit the components being produced.
Any fixture can be swapped over in just six minutes. The adaptable arrangement eliminates the need to exchange an entire workholding system when switching components and workpiece materials, offering a more versatile alternative to bespoke, dedicated fixturing.
High-density workholding maximises weekly throughput in each Okuma flexible manufacturing cell to match assembly demands. In one instance involving an optimal run of 150 aluminium parts per week, 15 at a time are fixtured on each of four sides of a hollow, high-strength, Tenzaloy cast aluminium alloy tooling column, which was manufactured by Abbott in the US and supplied by 1st MTA.
The lightweight yet strong and vibration-damping column prevents the maximum pallet weight being exceeded, while allowing Op 1 and Op 2 to run in just over 1 hour 10 minutes, allowing 30 parts to come off completely machined each time.
The setup incorporates Finnish OK-Vise workholding, as well as US-made Mitee-Bite Pitbull clamps for Op 1. There are two of the tool steel knife edges in a top rail and another in a bottom support rail, all three of which grip securely onto the edges of the workpiece.
For Op 2, Mitee-Bite Uniforce clamps secure the components. They expand in two directions to hold a pair of components simultaneously against fixed rails, leaving no witness marks on the finished component.
Pic: A close-up of the clamped end coversMr Vicarage says that 1st MTA’s Abbott system has provided five years of daily service without requiring any replacement parts. He also emphasised the accuracy achieved: "Due to the excellent workholding rigidity, gear pockets are machined to within a few microns, and this is maintained over the entire face of each side of the tooling column, with no variation.”
For heavy cuts on 250-grade cast iron workpieces, a three-operation setup employs an Abbott column equipped with hardened fixtures, as well as low-profile Pitbull knife-edge clamps to avoid tool interference. Despite the heavy cuts being taken including with CBN and ceramic tooling, the rigid clamping comfortably handles aggressive 4mm depths of cut and 11.5mm diameter drilling into the solid, without pull-outs or stability issues.
Mr Vicarage concluded: “The comprehensive variety of workholding solutions supplied by 1st MTA means that we have complete control over manufacturing efficiency, flexibility and precision. In addition, the longevity of the clamping equipment means that it is very cost effective.
“As we move increasingly from stand-alone production platforms to pallet-based systems, we will continue to take advantage of the multiplicity of clamping arrangements that are available from 1st MTA with a view to maximising multi-component fixturing and unattended running.”