The system, called the CGF Profile Autoduct is designed for the production of galvanised steel, straight duct sections for HVAC applications.  THK SSR LM Guides have been installed to provide precision movement at two distinct stages of the duct manufacturing process.

The CGF Profile Autoduct system is unique in that it produces a fully formed duct section, with a double, hollow type flange configuration and a pressed and folded closed corner seam, in a single, straight line, fully automated manufacturing system.  

The system is capable of forming high quality ducts from galvanised steel, in gauge thickness from 0.5mm to 1.25mm, with the cycle time from steel coil to finished duct typically taking less than one minute.

In operation, manufacture starts at a de-coiler station, where up to six in-line or double decker spaced, 5 tonne steel coils are mounted for feed into the system.   Typically the galvanised steel is 1.5 metres in width, although 2 metre coils can also be used.   The variance in width is achieved by moving the roll forming heads on THK’s BNT left hand and right handed ballscrews and SHS caged ball LM guides to accommodate the steel coil width.

The steel from each coil is fed into a dedicated pair of pinch rollers, which are controlled by an independent clutch to enable any one of the coils to be fed through the system individually.

The steel is fed automatically on to the main drive rollers and through levelling and bead stiffening sections to a notching station.  Here pre-cuts are made in the sheet at precise locations to prevent the steel from splitting when the folding operation occurs further down the line.

It is at the notching station that the THK SSR LM Guides are installed, to provide precision movement in the Y axis of the notching unit.  

From the notching station the steel is fed to a pittsburg unit, which slits and rolls the female pocket on the back end of one blank and the male 90° edge on the leading edge of the next blank, in a single pass.

Movement of the pittsburg unit transversely is generated by two further THK SSR caged ball LM Guides, to give straight, smooth, fast and accurate motion.

The unique construction of the THK caged ball LM Guide system, which eliminates contact between bearings in the block and maintains initial lubrication for more than 30,000 km of travel, ensures that factors such as friction and wear are minimised, providing Firmac with a reliable and maintenance free linear motion system.

One of the latest CGF Profile Autoduct Systems to leave Firmac’s Scarborough factory has been installed at a Taiwanese duct manufacturer; this is the second sale in Taiwan for the CGF system, which is the largest in the Firmac range.

Steve Parker, General Manager at Firmac explains, “We have a worldwide customer base across our entire machinery range, for which we provide a full package of support services.   However, it is obviously in our customers interests, from a cost basis, if we can minimise their service requirements.  To this end, reliability and longevity of individual components within the system are essential.

This is one of the key reasons we chose the THK LM Guide system with caged ball, as it provides us with the accuracy and longevity required to ensure effective operation.

We changed to THK from a previous supplier, as the combination of superior performance and longevity offered by the product, coupled with competitive pricing, good deliveries and an excellent support package from THK, provides us with the best all round deal for both ourselves and our customers.

Additionally, the global nature of the THK organisation means that local support is available in Taiwan in the unlikely event it should be required.”

For further information contact Diane Gregory, THK U.K. 26 Alston Drive, Bradwell Abbey, Milton Keynes.  MK13 9HA.  Tel: 01908 222159.  Fax: 01908 222161.  Email:  dg@thk.co.uk