Located on a 55,000ft
2 facility in Stroud, Impcross Ltd has a rich history of manufacturing high-end components for the military, aerospace, Formula One, petrochemical and motor-sport industries with a work-flow that was 75% prototype and small-batch work and 25% long-run production.
However, the appointment some five years ago of a new CEO saw a ‘re-alignment’ of the family-owned business and further investments that resulted in it achieving the aim of becoming 25% prototype- and 75% production-oriented — and focused more on the aerospace OEM sector.
These changes have seen staff numbers almost double.
Ensuring that it maintains long-term partnerships with its aerospace customers (these include the likes of Safran, GE, UTC, Messier Dowty, BAE Systems, NSK, Honeywell and Rolls-Royce), Impcross has a comprehensive list of aerospace OEM accreditations, as well as ISO:9001, NADCAP Chemical Processing and NDT accreditation — and AS:9100 Revision D.
Underpinning these accreditations is a lengthy plant list of metrology equipment and quality management systems from Andover-based Mitutoyo (UK) Ltd (
www.mitutoyo.co.uk).
Commenting upon the partnership with Mitutoyo, Impcross operations director Steve Arnold said: “Not only has Impcross worked with Mitutoyo since its inception in 1994, my father — who founded the company — previously owned another business. He has worked with Mitutoyo since the 1960s.”
Impcross has two Mitutoyo co-ordinate measuring machines (CMMs) — a BHN 706 and a Euro C 7106 — that have been on-site for 18 and 24 years respectively; and thanks to continual software updates, regular calibration and maintenance programmes, they are still in daily use.
To accommodate on-going growth, the company is about to install a third CMM — a Mitutoyo Crysta Apex S7106.
Running alongside the CMMs is a host of other Mitutoyo equipment, including Linear Height 600 2-D motorised height gauges, PJ300 profile projectors, numerous digital bore gauges, an SJ401 surface roughness measuring unit, Surftest 211 portable surface roughness measuring units, a Contracer CV4500H4 and a Roundtest RA2200AH.
Demanding operation
On a monthly basis, Impcross will manufacture — and carry out first-off inspections on — over 500 different component types, which is why the company runs its machine shop and metrology department 24/5, with full traceability on its production and quality procedures.
Two years ago, Impcross won a contract to manufacture reverse-thruster valve housings for a defence customer. Manufactured from aluminium to minimise weight, these housings feature a hose-connecting thread that has to withstand a pressure of 5,000psi.
To ensure that the thread could accommodate this pressure, the customer developed a special thread geometry (in conjunction with its tooling supplier) before awarding the contract to Impcross.
The thread form is tied to a tolerance of less than 50µm; and to ensure that it is held to specification, the OEM aerospace customer supplied Impcross with a Mitutoyo Contracer CV-4500 to measure the thread form on every single part.
Another critical component manufactured by Impcross is a valve sleeve guide that works in conjunction with the thrust valve housing.
This stainless-steel component has a cylindricity and parallelism bore tolerance of 1.2µm over its 127.7mm length — and a 2µm surface finish tolerance. Moreover, the external turned features are all tied to a tolerance of 5µm.
Impcross, which manufactures more than 200 of these sleeve guides every month, says that inspecting these parts would be impossible without the Mitutoyo Roundtest RA2200AH.
Slick operation
Mr Arnold says that with this level of production, the quality assurance department has to be as ‘slick’ as the shopfloor operation.
“All our metrology equipment uses the latest software updates from Mitutoyo, and there is complete conformity between our equipment, processes and reporting.
“Furthermore, we have Mitutoyo’s MCOSMOS CAT 1000 software integrated into our metrology equipment. This allows us to download the CAD/CAM files for components from our servers directly to the Mitutoyo machines.
“In the case of the CMMs, we can download the part model directly from our CAM software and set the datums on the CMM according to our models.
“This level of integration is key to the productivity of our metrology department. We recently won a defence-industry order for a family of gyroscope components required in batches of 50,000.
“To process this high volume of parts, our CMMs will use a grid fixture plate, and they will apply SPC to record data for our client. They will regularly check more than 50 parts an hour and run 24hr a day.”
In conclusion. Mr Arnold said: “Impress is a business that ‘captures data’ at every level, and the Mitutoyo equipment has been integral to our success.
Equally important is the fact that our aerospace customers know we have a quality assurance department filled with high-quality metrology equipment.”