Grinder creeps towards flexibility

Most toolrooms and job shops are equipped with a reciprocating surface grinder. However, with the current trend for increasing machine flexibility without sacrificing floor space, the ability to carry out creep feed grinding operations on such a machine would make good business sense. Simon Simmons talks to Industrial Machine Tool Services, a company offering this benefit.

Based in Rochester, Kent, IMTS Grinding Technology  has a dedicated workforce with a broad- based expertise in grinding applications. The 12-employee company has developed the necessary hardware to add to a surface grinder, giving it the ability to function as a creep feed grinder.

"The development started when a customer asked if we could rebuild an old creep feed grinding machine. We took the job on, but soon discovered that the hydraulic valve which controls the table feed would be difficult to replace," explains Charles Thurston, managing director of IMTS.

    "Not being the sort who give up easily, we contacted a Swiss valve manufacturer who claimed to be able to provide a solution to our particular problem. They did, but it took 12 months of development work to achieve the necessary level of control. It is vital that sudden lurches are avoided during creep feed grinding, and this is why the valve plays such an important role. In order to maintain a smooth, constant motion, the valve must not be affected by changes in the temperature and pressure of the hydraulic oil. The valve also has to be able to accept a pressure differential from both sides of the feed cylinder. This is why the development period was so long, but we now have a valve that can accurately control the feed rate down to 1 mm/min. And we now have a reliable method of transforming the standard surface grinder, giving additional capabilities without losing any of the original functionality:"

Developing Hardware

Following the success of the first rebuilt machine, and enquiries for new machines, IMTS developed the creep feed hardware and control system for Chevalier surface grinders. "We have an agreement with Dugard, the UK agent for Chevalier, which allows the base machine to be supplied directly to us. These are modified to our specification, including a larger, more powerful motor and increased lubricant flow. We then fit the hydraulic valve, control system and any other special features, such as profile wheel dressing, requested by our customer," says Mr Thurston.

    Although the retrofitting of the creep feed process was started as a side line, it has grown to such a level that it is now becoming a substantial part of the company's business which largely consists of cylindrical and internal grinding applications. With a price tag of less than £50 000 for a new machine, the extra capability offered by IMTS is very affordable. In the next year, four of these new machines are already in use at various locations around the UK and one is being used by a customer in Israel, with a second machine currently being built. With two, 6000 ft2 units fully employed, Mr Thurston is looking at other locations: "Last year we built 12 machines, including CNC cylindricals and we expect to build around 18 machines this year. This means that we need to expand, to cater for the increased workload.

    "Besides the Chevalier machines, we have other special purpose machines under development. Because we are a small company, we can dedicate the time and focus the skills needed to provide a solution to a problem."

Recognition of the skills held by the company came last year when IMTS won a Small Business of the Year award for 'Innovation and Technology'. For all the projects undertaken by the company, the product and process development is carried out in-house. One such project has seen the company develop an automated grinding process for pneumatic power tool manufacturer, Desoutter. By using a PLC and stepper motors - offering a cost saving compared to CNC, the company can control the process to perform interpolation operations. The fully automated process equipment is capable of finishing components, and all the control software has been written by IMTS's two software engineers. "We have a number of large OEM customers who present us with some difficult projects. We always put 110 per cent into achieving the desired result," concludes Charles Thurston.