Minimal production manning thanks to punch press

Following the installation of an LVD Strippit 1250 H30 punch press equipped with an automated load/unload system, lighting equipment specialist Keylighting has been able to adopt minimal manning

Following the installation of an LVD Strippit 1250 H30 punch press equipped with an automated load/unload system, commercial lighting equipment specialist Keylighting has been able to adopt minimal manning production techniques.

The machine is a major part of a recent expansion programme for the Keighley-based company, including a move to enlarged premises and the purchase of a number of automated systems including a powder coat paint plant, a robotic wiring system for lighting chassis and an automated panel bender for folding the higher volume sheet metal 'boxes' that house the lighting chassis.

Keylighting is owned and managed by Nick Robinson who admits to setting up the company, at the beginning of the 1990s, almost by accident.

He recalls: "We were importing a variety of electrical goods from the Far East and were asked if we could supply a particular type of light.

Having said that we could, we found there were problems with supply -which resulted in us having the light made to our own design.

Since then we have expanded into commercial lighting equipment and we are now a leading supplier into this sector." Sales tend to be made through the electrical wholesale trade into local authorities, the NHS, retail groups and other commercial and industrial end users.

From one product in 1991, Keylighting now has a range that fills a well-produced 70-page brochure, and offers competitive lighting solutions for the majority of requirements.

"Most of our products started out as customer requests," says Nick Robinson.

"However, we have now reached the stage where we do some speculative product development work as well.

We are good at engineering sensible solutions that result in lighting systems that are straightforward to build and offer highly competitive performance and pricing.

That essentially has stimulated further demand resulting in the recent manufacturing expansion," he maintains.

The company's sheet metal requirements are fairly straightforward.

All of the box type work and metal components produced between 0.5 mm and 1.0 mm thick are punched from steel sheet or Zintec, which is well within the Strippit's 9.5 mm capacity.

They are then bent to form on either a folder or one of four CNC press brakes.

For the last four years, the mainstay of flat pattern production has been through a Strippit 1000XP mechanical punch press.

"We have been very pleased with the XP," Nick Robinson relates.

"It has been a very productive and must have made over 40 million hits." He then describes how his company became more productive by breaking with convention and punching two sheets of material simultaneously.

"We got away with it because the sheet is quite thin, allowing us to use a die clearance of 0.2 mm.

Nevertheless, we reached a point where we needed additional punching capacity.

I felt strongly that we should go down the automatic load/unload route so that we would have the capability to increase productivity further with 'lights out' production." As well as offering unmanned running, automated handling is quicker than manual load/unload as the system on the Strippit H30 can exchange sheets in just 22 seconds.

Automated handling alleviates any handling problems associated with large, thin gauge metal sheet.

Keylighting produces flat patterns mainly from cut blanks, but at up to 1,850 mm by 850 mm and due to the low mechanical rigidity of the material, they are extremely difficult to load manually.

Apart from automated work handling, Keylighting was keen to have a machine that offered fast punching rates and a larger capacity turret.

On the existing XP, use of two multi-tools provides 31 tools distributed between 20 stations; on the new machine Nick Robinson was keen to have more tooling available to maximise design flexibility without the need for tool changes in production.

He also wanted large diameter fixed stations so as to have bigger slitting tools available.

"Ultimately, we concluded that the Strippit machine was the only system capable of meeting all of our requirements," he recalls.

"It's possibly slightly larger than we really need, but the 40-station turret provides high tooling flexibility." He describes how Keylighting was in two minds whether it should opt for Strippit's consistent stroke mechanical or programmable electro-hydraulic punching system.

"In the end we went for the latter.

That has been a very good decision as it is very flexible and makes the setting of form tools and threading tools much easier.

Also, the Smart Stroke(r) punch system optimises punching force requirements according to the material thickness," he says.

Smart Stroke encompasses a fully programmable ram with built-in stroke profiles.

The hydraulic drive reduces noise and shock, and the Strippit's GE Fanuc control automatically calculates the optimum ram 'hover' for each stroke to minimise the punching stroke and nibbling routine times.

The Strippit 1250 H30 will accept material up to 1,250 mm by 2,000 mm and has a rapid traverse speed of 81 m/min.

It has a hit rate up to 900 hits/min and a positioning accuracy of 0.025 mm.

The 42- station turret has a station index time of 0.9 sec and its Smart ClampTM automatic clamp scanning sequence minimises 'no punch' zones to further improve material utilisation.

As Nick Robinson concludes: "A target for the new machine has been to significantly reduce the amount of second operation work that we need to perform before the flat pattern is bent to shape.

For instance, we can now thread in-cycle.

We couldn't do that before - as well as producing all of our shapes and forms from the standard turret.

"Having 42 tools available means we can reasonably expect to design everything within that tooling limit and use a constant die clearance for all of our production.

The advantage of that is that change-over time between jobs is minimised," he says.

"As the application develops, the versatility of the machine - combined with its ability to operate in a minimally-manned environment - is a major asset to our company," he concludes.

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