in Vol. 3 - May Issue - Year 2002
Reusable Solutions for demanding Masking Problems

In the Spotlight

Gerard Poly Mouldings is a UK based engineering/moulding company specialising in the design and manufacture of moulded masking and protection to the gas turbine industry and other high specification industries. The main areas of focus for masking are grit blasting, shot peening, metal spray, painting and vibratory polishing.

Today masking is a significant factor in the manufacture and repair of gas turbine engine components, mostly it is time consuming and expensive. Gerard Poly Mouldings (GPM) has focused its energies over the past 18 years, building on a precision engineering background to develop high quality moulded masking at affordable prices.

The blast, peen and vibratory polishing masking is produced from PU elastomers in varying grades and hardness to suit the particular application, it is also pigmented to aid recognition as well having raising identification characters.  The PU is highly durable for peen applications up to Almen 10A intensity, for peen intensities higher different material technology is applied.  The English company's main aim for its masking is to provide accuracy and ease of use for the operator.
Most shot peening applications that call for moulded masking are blades and vanes, for these applications masking are customized to suit the individual customers' machine leaving the customer nothing further to do in respect to masking.  In addition to small masks, much larger masks (up to Ø1000mm / 40") are produced for fan discs, spools and turbine discs.  This is an area which has been neglected in the past owing to peoples perception of prohibitive tooling costs, GPM where possible try to absorb tooling costs, the basis of this ideology is that there is more than one company shot peening PW4000 Fan Discs, CFM56 Compressor Blades, etc.  This ideology also enables small companies to afford moulded masking for low volume jobs whereas before it would have been unjustifiable.
On a number of occasions machine manufacturers once having outlined the products lines that are aimed at the new machine have requested the English based company to handle all aspects of masking design and manufacture.  Apart from the component masks, holders are also produced in high durometer PU, these typically have a stainless steel fitting cast into them to interface with the machines spindles.
In the past decade airfoil-coating technology has progressed significantly and more components now have blast, shot peen and vibratory finishing to their airfoils. GPM pioneered back in the 1980's airfoil trailing edge masking, until that time customers had masks for non-gas flow areas but were taping the trailing edges.  Prevention of damage to airfoil coatings along trailing edges today is critical (as the cost of stripping and re-coating single piece items is high).  The trailing edge masking is accurate and offers repeatability.

For Information:
Gerard Poly Mouldings
West Point Business Park
Ranson Road, Chilwell
Nottingham NG9 6DX, England
Tel: +44.115 972 6540
Fax: +44.115 946 2163
e-mail: GPMUK@aol.com