Star GB: Three decades of top turning technology

It’s a busy time of the year for open houses, and Star GB’s event, which took place in November, had dual significance. Not only did it mark the sliding head specialist’s first event since the pandemic struck – it also commemorated the company’s 30^th anniversary. Dave Tudor headed off to Derby to check out the new technology on offer. 

With around 110 pre-registrations from 55 different companies, interest in Star GB’s event was as strong as ever as the manufacturing fraternity comes back to life following the ravages of COVID-19. Machine wise, there were seven models on show, but in terms of new technology, the highlights were new SL-7 and SR-32JIII sliding head turning centres, an FMB Turbo RS 3-38 bar feeder plus the latest developments in high pressure coolant and mist extraction. Let’s take a closer look.

FMB Turbo RS 3-38 bar feeder

The Turbo RS 3-38 bar feeder is an evolutionary development from the popular Turbo 3-36 unit that Star has been selling for years. As Star GB’s operations manager Alec Warner explains, the company will continue to sell the older variant, but the new product offers a number of advantages. 

“The 3-36 works with lathe steadies on the back of the main spindle and on the front of the bar feeder and the section in-between is the telescopic area,” he affirms. “The problem here is that as the bar is fed through – going from 3m down to 2m down to 1m for example, there is a transition area between the two steadies where the bar isn’t fully supported.

“The new Turbo RS 3-38 solves this problem. It still uses the lathe steadies but we’ve got a long tube that’s connected to the back of the main spindle that moves in and out of the carriage along the bar feeder. The idea of the tube is that it moves the poorly supported transition area further down the bar feeder where there is better hydrodynamic support either side thanks to the channel and tube configuration.

“The other big benefit with the Turbo RS 3-38 is when we go from guide bush to non-guide bush. On the old system we’d have to move – and re-secure – the whole carriage. On the new model, because the tube is moving with the headstock, there’s no need to move the carriage. It makes setting up significantly quicker.”

SR-32JIII

The Star SR-32 CNC Swiss type automatic lathe, in its various incarnations, remains the most popular model in Star’s portfolio. The latest version, the SR-32JIII is an evolutionary succession from the SR-32JII; Alec Warner believes the additional enhancements will be even more popular with customers.

The main difference is an improved specification – adding a 7 bar sump flush coolant pump on the sub-spindle as standard – ideal for preventing swarf and chips from building up in the sub-collet assembly – and only available as an optional extra on the previous version. In general, the re-design of the working envelope will promote much improved swarf evacuation from the machining area.

“The back platen however has changed significantly from the SR-32JII,” Mr Warner reveals. “Before, we had the fixed casting with the platen behind it moving up and down with the Y2 axis. Now, we’ve got the fixed part of the platen with the Y2 axis moving in front of it, so it’s a lot more rigid than its predecessor and metal removal rates are improved.”

The SR-32JIII series offers a choice of models for even more flexibility. The Type A features a back working static six spindle platen with no Y2 axis on the rear. The Type B however incorporates an eight tool back working spindle unit with Y-axis control. Both variants are coolant through tool compliant and various power tool units are available. The Type B configuration historically is more popular with UK customers due to its greater versatility.

And good news spreads fast it seems. The first SR-32JIII in the UK has already been sold to Hertford-based precision subcontractor Qualiturn Products Ltd.  

Cool running

Other new technology on show included a new series of Hydrajet high pressure coolant systems from Warwick-based Pumps & Equipment – a long-term Star partner. There are four variants in the new range and all are Star-branded and colour coordinated so they certainly look the part aesthetically when located alongside Star machines.

But it’s not all about aesthetics. The four new models are designated UB20-2000 with different suffixes to denote specific performance characteristics. All have a maximum pressure of 140 bar, 20 litre maximum volume, twin filters, eight M-code controlled outlets, 150 litre integral tank, 7.3 inch Mitsubishi touchscreen and built-in noise suppression system. 

But there are choices. The -8T suffix is the standard manual filter changeover model; the -8TA ships with auto-filter changeover capability; the -8TV features a variable speed control; and the -8TVA is the all-singing, all-dancing model which comes with both auto-filter changeover and variable speed.

Small talk 

Star’s new SL-7/10 ultra-compact sliding head turning centres are designed with manufacturing small components in mind. Specification-wise the machines are very similar but one difference straight off the bat is that the main collet on the SL-7 is F10 whereas on the SL-10 it’s F15.

“This represents a brand-new range of machines for Star which will target the micro machining sector,” Mr Warner advises. “We’ve had a small machine – the SR-10J – in the range for years but this machine was designed for an entirely different market. With the SL-7/10 we can go down to 0.8mm diameter bar and of course it can be used with an FMB bar feeder for full-scale production.

“The main differentiator between the SL-7/10 and the SR-10J however is with the tooling that can be used,” he adds. “On the latter, there are only four stations for back working which can be a little limiting. In contrast, the SL-7/10 has six back working stations of which four are driven.

“Not only that, of these four, two can be used with cross working stations so you can machine cross holes on the sub-spindle, effectively increasing the overlapping opportunities on the sub which will reduce cycle times even further. The better you can balance the main and sub-spindles, the shorter the overall cycle time will be.”

On the main machining spindle side, the SL-7/10 has five driven tool positions. There’s a drilling arm which can move up and down the platen and as this is a modular system, it can comprise four or an optional six stations.

“The other benefit is that a variety of attachments for whirling, slotting, gear hobbing, angled drilling and polygon machining can also be accommodated without having to re-engineer the platen arrangement,” Mr Warner adds. “All of these are cartridge adaptors which can be easily sourced off the shelf.”

I can see the SL-7/10 appealing to a wide variety of sectors like connector and medical component manufacturing. Its dimensions visually are clearly ergonomic. The machine is only 795mm deep, but it is taller (1,815mm) than the SR-10J – due mainly to the vertical orientation of the platen. Opinions will naturally vary but the accessibility and internal layout of the machine is definitely one of its strong points. A twin cylinder door ensures smooth access and process security when using high pressure coolant.

There are a few other additional subtle differences between the SL-7 and SL-10. We’ve noted the SL-7 utilises smaller main and sub collets and a smaller guide bush housing, but also the stick tooling is 8mm shank compared to 10mm on the SL-10. On the SL-7 the parts are collected in the machine receptable (front of machine panel) rather than transferred along a part conveyor to the side of the machine.

Smart air filtration

Completing the new product line-up was the Exomist HPM 1000 high performance mist collection unit. Manufactured in Italy, available from UK agent Filtration Service Engineering (FSE) and offered as an optional extra by Star GB, the system is compact, offers a 570 cfm nominal air flow rate, weighs just 80kg and is designed to offer easy access and maintenance. Star’s most popular model in this range is the larger HPM 2000 which is available on any machine above 20mm.

“The Exomist unit is very energy efficient and versatile,” Alec Warner explains. “It’s fitted with a two-speed inverter drive system which means it can be used with both standard and high-pressure coolant. The unit interfaces with the machine tool’s CNC so it knows when it’s in cycle; when high pressure coolant is running and when the machine’s idle, it doesn’t draw any power. The interface also means the user is alerted of any blocked filters via the CNC’s display.”

Star GB
www.stargb.com