Faster modelling for railway engine maker

Winson Engineering, which designs and manufactures narrow gauge railway engines and steam locomotive kits, has been able to reduce its prototype model lead time by a third with Edgecam software

Winson Engineering designs and manufactures narrow gauge railway engines and steam locomotive kits.

Following the integration of EdgeCAM part programming software with CAD design software from SolidWorks, the Daventry based company has been able to reduce its prototype model lead time by a third.

Compared with keying in data on components at the machine control system, the EdgeCAM off-line system from Pathtrace of Reading has dramatically shortened the programming of the company's 17 CNC machines that are producing 50,000 parts a month.

In addition, confidence levels in EdgeCAM are now such, that CNC programs no longer need prove-out and machining strategies have improved tool life and component surface finish.

Winson Engineering is a world-leader in full-scale narrow gauge steam locomotive manufacture.

It has recently completed a train set involving locomotive and carriages for a Japanese theme park.

However, the major growth area of the business is now Winson Model Technology, which was established three years ago to manufacture locomotive kits for would-be model engineers.

It was the move into kit manufacture that dictated the need for CAD/CAM as Winson Model Technology operates in a production environment.

It has to meet tight deadlines and anything that can reduce the design to manufacture lead time is welcomed.

Initial investment in 3-D solid modelling CAD provided a much reduced time to finalise model design from the usual eight weeks.

As the kits are produced in batches and popular selling models will be re-issued in the future, there was also a need for CNC program storage which led to the purchase of EdgeDNC while computer-based program preparation completed the set.

"We waited some time before investing in computer-aided manufacturing software," Mark Watkins recalls.

"This was partially because we were quite good at manual programming and because we wanted the right system to complement our CAD facility.

A direct interface with SolidWorks was a desirable feature but we also wanted a system that was flexible and easy to use in its own right and capable of producing concise, easily comprehended code," he maintains.

The company compiled an identity parade of what Mark Watkins describes as 'the usual suspects' though these did not include EdgeCAM.

"The systems that we looked at initially ranged from 'no-hopers' to quite good but were not what we wanted," he recalled.

"We used an apparently simple solid brass hornblock component as the test-piece which included open pockets and an inclined face.

While some systems simply couldn't cope with the inclined face, others generated miles of code to achieve it and certain CAM systems were really like using a sledgehammer to crack a walnut.

Equally, we were concerned about post-processor costs; though most of our machines have the same control, there are variations in the software that need to be addressed." In the end it was a machine tool supplier that directed Winson onto Pathtrace's EdgeCAM.

"We were impressed by the response," Mark Watkins remembers.

"We accessed the Pathtrace web-site, sent them an e-mail and two days later they were in front of us to demonstrate their capability on the SolidWorks file.

Within one hour the program was ready.

We tried it and it worked, so we bought the EdgeCAM package." A big advantage for Winson was the availability of a single user network licence for EdgeCAM that allows any one of five SolidWorks seats to access it for programming.

Two further important points were the Code Wizard, which has enabled Mark Watkins to customise post processors for each of the CNC machine tools, and user training, that was tailored directly to Winson's requirements.

"We have a lot of faith in EdgeCAM," Mark Watkins enthuses.

"In general, the amount of time that is spent on programming has reduced significantly while the toolpath simulation is good enough to dispense with prove-out.

Component quality is better, insert life has improved and Pathtrace has provided good back-up," he says.

Mark Watkins has always been committed to the use of CNC machined components made from solid material which eliminates the need for pattern making and the manufacturing process is largely immune from any unpredictability associated with castings.

It also reduces dependence on outside suppliers for the model company, other than for raw material, as it now manufactures the great majority of components in-house.

Component dimensions range between 6 mm and 300 mm cube, while turned diameters cover the range from 3 mm to 300 mm.

Materials tend to replicate those that would be used in a full-sized locomotive including cast iron, brass and steel.

Machined accuracy is generally in the range ? 0.1 mm, a tolerance that most model engineers would be very happy to achieve with consistency and, according to Mark Watkins: "It is far easier to present a quality model to the customer.".

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