Product category:
Washing and pretreatment
News Release from: Stowlin Croftshaw | Subject: Croftshaw Cool-Phos pretreatment process
Edited by the Manufacturingtalk Editorial
Team on 22 March 2001
Finishing the job - a recipe for growth
Sheet Metal Products carried out a thorough process and market investigation before installing new preparation and coating equipment.
The growth of the subcontract engineering base in the South-of-England has in part been due to the downsizing of large OEMs in the automotive and fmcg sectors However, once started, investment in plant and machinery for any small company is a decision that is never taken lightly, more with trepidation - yet, fortune favours the brave, we are told
This article was originally published on Manufacturingtalk on 30 Jan 2008 at 8.00am (UK)
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At Sheet Metal Products (SMP), growth is based on a combination of innovation, product quality, and always being responsive to customers needs.
This motis operandi has recently seen the installation of a bespoke finishing cell, which includes the unique properties of a Cool-Phos pretreatment process at the companys' Rochester site, as Managing Director, Bob Shaw, explained.
'Our growth has always been based on meeting the needs of our customers and saw us move to our present site in 1996.
Further reading
Non flammable degreasing formulation
Vaposol AMC, from Stowlin Croftshaw, is a non-flammable formulation with no components classified with the prohibited risk phrases R45, R60, R62 or R63, designed specifically for vapour degreasing.
Cleans, phosphates and dries in one process
A pre-treatment process that combines the benefits of vapour degreasing and aqueous phosphating produces a better key for paint or powder coating and also protects the parts against corrosion.
A fine finish at the point of sale
The installation of the largest UK Cool-Phos combined degreasing, phosphating and drying system is critical to finishing process at Jack Sayers Products.
This has also meant investing in both the right technology and cost-effective manufacturing process.
We can produce quality sheet metal work and OEM components from design to finished product.' Coinciding with the move to its present site, SMP took delivery of an Amada Arcade 210 CNC punch press that added productivity to the skilled labour, and saw turnover triple.
'We are manufacturing product for a wide variety of industry sectors.' stated Bob Shaw.
'Typically, we will manufacture intercom and speaker boxes that you would find in banks and building societies, racking and shelving for shops and offices, as well as enclosures for the electronics sector.
We will take in a design in IGES or DXF file and load the CNC data at the machine, cutting to 0.
1mm tolerance and repeatability in stainless steel, mild steel, aluminium, brass and copper.
The Amada Arcade allows us to cut within a range of 0.5mm to 3mm thickness and turn round prototype components within 24-hours.' Increasingly SMP has been required to reduce lead times and produce a completely finished product.
This has seen an expansion of the present operation and the creation of a bespoke Finishing Cell.
'We traditionally sent assembled product out to a trade finisher but have not been able to completely control the manufacturing process.
Both quality and delivery increasingly became a problem and got to a stage where we could have lost customers over the finishing operation.' stated Shaw.
Over a period of eighteen months, Bob Shaw undertook a thorough investigation of the available processes.
'Although air-circulating ovens seemed to be the preferred method of curing, I believe it is the pre-treatment process that is the important factor, enabling a good key for the powder coating.
The cell was created with this in mind.
A 2.5 x 1.2 meter open surface Cool-Phos combined degreasing, phosphating and drying system was installed by pretreatment specialists Croftshaw Solvents in July, along with a Nordson powder coating booth and Maywick Raymaster radiant oven and conveyor system.' 'Vapour degreasing was never an option,' continued Shaw, 'it leaves a residue on the surface and has to be wiped.
We could not afford that; we had to have a completely clean component.
With the Cool-Phos system it thoroughly cleans and degreases even the most complex component and the phosphate process is a bonus, giving a completely clean 'blue finish', ready to handle from the tank directly to the powder coating booth.
It is also an environmentally friendly process and unlike other processes and system suppliers, all chemical and equipment tests are regularly undertaken by Croftshaw technicians.
Croftshaws' good stewardship includes the removal of empty barrels and chemicals when required.
With water-based treatments not only does it entail a number of stages, but where we spot weld, the overlap on the join would see the water stain the side and cause problems in the ovens.
The solution would be another oven prior to coating - a totally impractical and costly option.' A typical finishing route for a nest of components would see them loaded into the motorised 'basket', with a carrying capacity of 115kg, which is raised and lowered into the Cool-Phos tank.
SMP currently jig each component before it goes into the basket, enabling an easy 'hook-up' in the spray booth.
Once in the tank, the components are prepared for painting/powder coating as they are lowered into the vapour zone above the boiling Cool-Phos solution.
Vapour condenses on the components until the temperature equalises at 381degC.
This degreases the surfaces and removes loose dirt as it is flushed off by the condensed Cool-Phos.
Dipped into the solution for 1 - 2 minutes, a phosphate conversion coating, a thin crystalline bond that is integral with the metal substrate is added.
The phosphate coating increases the surface areas available and provides an excellent 'key' for paint, powder and other finishes.
Additionally, Cool-Phos presents a physical barrier against moisture, thus inhibiting rust in the event of a damaged surface.
After dipping, the coating basket is raised into the vapour zone where it is spray-rinsed with cooled Cool-Phos distillate to remove traces of phosphoric acid.
Residual condensate flash evaporates as the basket is removed from the tank.
The whole cycle takes only five minutes.
Transferred directly to the Nordson powder booth the parts are given the required finish using a Courtauld powder.
Coated workpieces are carried by a variable speed MAY300 light-duty overhead conveyor between the two internally facing walls of the Maywick oven, which consists of four tiers of double gas-burner panels.
Oven temperatures and conveyor speeds are regulated from an adjacent control panel, enabling curing temperatures to be modulated as required.
Each new product is tested for temperature and powder curing and recorded for future batch manufacture.
Creating the Finishing Cell required an investment of GBP100,000 including the unit cost.
However, with previously subcontracted-out trade finishing costs at GBP100,000 per annum, Bob Shaw believes he has a cost-effective process with a reasonably short payback time.
A call from a customer requesting the production of 15,000 finished fire collars in four weeks, was typical of the change that has driven the investment.
'Without the finishing operation we simply could not have considered the job.' he concluded. Request a free brochure from Stowlin Croftshaw ...
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