Indian summer

Building upon previous orders for a German turbocharger manufacturer and successes in the diesel fuel injection and drilling tool market sectors, Curtis Machine Tools of Colchester has recently won an order valued at £800,000 from an Indian customer to supply three Vector twin spindle grinding machines for the production of a high volume automotive component.

The component is ground in two operations on the Vector: the first operation – controlled by in-process gauging is to grind a spigot, profile and a face with angle approach grinding. The operation is completed using vitrified a CBN grinding wheel with a rotary full form diamond roll dresser.

The components are stored in the Vector on two pallets. The integral 3-axis automatic loading system picks the components from the pallet and unloads/loads the second work chuck whilst grinding is being simultaneously carried out on the first chuck.

After unloading, the component is transferred via a servo-controlled axis to a secondary grinding station integrated into the Vector, where the second vitrified grinding wheel grinds a face parallel to the face ground in the first operation. After grinding, the component is transferred by the same servo axis to the post process gauging station where the overall thickness of the two ground faces is measured. Automatic size correction of the second grinding process is controlled by feedback from the post process gauge.

Curtis reports that the key to success in winning this order is that its solution provides a cost-effective package for this application as both operations are completed on one machine in a total cycle time of 13 seconds.

The company claims that the Vector grinding machine range, with its small footprint of 1,190mm by 1,850mm and fast and versatile integral loading system, offers more production per square metre of floor space than comparable competing machines. With minimal ‘dead time' and two second load time, the Vector Twin ensures optimised cycle times.

Additionally, innovative gauging methods promote accurate closed loop size control. Potential manual intervention and interruptions to process flow are minimal due to ‘warm-up' and ‘keep warm' cycles, thus ensuring statistical process capability is maintained. The compact Vector size confers good static and dynamic stiffness and excellent thermal stability – thus providing good workpiece geometry and short sparkout times.

Any potential contamination of the main working parts of both machine and loading system is virtually eliminated due to the Vector design that ensures coolant and grinding debris is contained within the sealed guard. The Vector also exhibits low running costs due to infrequency and ease of maintenance. A key parameter in the Vector concept is a low energy footprint, both in construction and lifetime usage. The ‘fit for purpose' approach ensures machine element masses are optimised for stiffness and inertia, resulting in high dynamic performance with minimal raw material. Also, high efficiency servo motors have relatively small mass to accelerate, thus drives are optimised to provide high performance with low current consumption.

Its hydraulic free design is an important environmental issue, and the small size of the ‘dirty' volume ensures air purity standards can be maintained with a low power extractor/filter. From a health and safety perspective, the machine incorporates a fully integrated grinding/parts handling system and two levels of guarding exist between operator and grinding wheel.

The robot loading arm with its ‘physical breakaway' protects the robot, ensuring simple and rapid recovery procedures. Finally, the sealed grinding area with integral mist extraction provides a cleaner environment for both operator and maintenance personnel.

With a relatively narrow defined work range the Vector is an effective tool. Focusing sharply on function, the customer gets what he needs to produce large quantities of high quality parts.

Curtis Machine Tools
www.curtisgrinding.com