Automated finishing at Leon Paul Equipment

Manufacturer of sports fencing equipment seeks the highest levels of quality and appearance

Posted on 09 Jun 2017 and read 260 times
Automated finishing at Leon Paul EquipmentMany fencers around the world, including winners at last year’s Olympic Games in Rio, use weapons manufactured by the London-based firm Leon Paul Equipment (LPE). What many of them may not realise is the level of expertise that goes into ensuring that the foils, epees and sabres are finished to a very high standard.

This focus on deburring and surface treatment has seen a further two vibratory machines installed in the factory, making a total of three.

Jack Jacob at LPE said: “Five years ago, we started producing a revolutionary pistol grip called Evolution for our epees and foils. It allows fencers to use a mouldable glue called Sugru to customise the shape of the handle and was well received within the sport.

“However, it presented us with the problem of how to achieve the required uniformity of mottling and smoothness on the surface of the aluminium investment castings.”

For the first time at the London factory, traditional hand-finishing techniques were replaced with automated de-flashing and surface treatment in a vibratory bowl supplied by Bletchley-based PDJ Vibro Ltd (www.pdjvibro.co.uk).

The company’s technical centre successfully trialled and then supplied resin deburring stones of tetrahedral shape combined with a second medium comprising conical stones to achieve a light burnishing effect. The bowl can accommodate batches of between 50 and 100 handles at a time and completes them in 1-2hr.

The technique proved so effective in terms of speed and repeatability that Leon Paul Equipment looked to see which of its other components could benefit from similar treatment.

Aluminium guards were an obvious choice, as the company had previously been turning foil guards on a lathe (after forming) in order to deburr the sharp edges before the final hand-polishing operation using industrial polishing wheels.

PDJ 1The viability of automating these tasks was established at PDJ Vibro, where sample guards underwent trials.

The process was so effective when subsequently adopted in Leon Paul Equipment’s finishing department that every guard for foils, epees and sabres is now deburred and surface-treated in this way.

Sharp edges and flash are removed from the aerospace-grade aluminium pressings that form the guards of foils and sabres. Epee guards, which are made from the same material, are similarly processed, but they still need to be
deburred on a lathe, as they are deep-drawn. All guards receive a smooth mottled finish that is more uniform than the previous hand-finished result.

Mr Jacobs says that about half of LPE’s guards are polished to achieve a glossy surface. “Polishing was carried out manually, which was a labour-intensive and dirty job, so at the end of last year, we decided to look at automating that process as well.

On the basis of the reliability of the first PDJ Vibro bowl, we contacted the company to explore the possibilities.

“After the successful completion of trials, in January they delivered a second vibratory bowl, a supply of small porcelain balls for burnishing our guards and a liquid polishing medium to ensure a bright finish.

“An operator puts 50 guards in the bowl and can then continue with other manufacturing duties, returning one or two hours later to unload a batch of polished components.”

Following the success of vibratory finishing for handles and guards, Leon Paul Equipment bought a PDJ Vibro vibratory trough for investigating the feasibility of automating the descaling of blades after heat treatment. Currently, the maraging steel components are shot-blasted manually to remove scale.

This process is essential to ensure the integrity of weapons, which have the blade brazed onto a tang; the process also ensures the aesthetic qualities of the products.

PDJ Vibro is giving guidance on how best to proceed, not only with descaling but also with polishing premium blades instead of shot-peening them.

The results so far are promising and have centred on the use of porcelain to finish around 50 blades at a time. Longevity of this medium has proved to be better than that of ceramic, minimising the consumable cost. Labour savings and consistency of result are,as always, the goal.

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