Piet van der Horst

Piet van der Horst

In 1970 Piet made welding his trade en since then he never stopped learning about that trade. By now he is well past his retirement age, but not welding is still not an option for him. It is not just work, it is a passion.

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Is cheap expensive?

Know what you buy

When a company purchases welding equipment, this is often done via the purchasing department, especially with larger companies. There is nothing wrong with that and usually this works fine. It becomes a different matter when the buyer has no (technical) welding knowledge and has not consulted with the users of the parts that are being purchased. In those cases it is often bought based on price alone and the sometimes enormous quality differences are not taken into consideration. That which seems to be cheap at first, will in most cases turn out to be expensive.

An example

A company with about 55 welders in the heavy construction. They weld almost exclusively with 1.2 and 1.4 mm filled wire. This means high welding currents, high duty cycle and high temperatures on the torch. This also means that the load on the contact tip, gas nozzle and torch is large.

After a few months a new production manager notices a few things. There are many welding errors, the consumption of wearing parts such as contact tip and gas nozzle is extremely high and the welders used contact tips with a larger bore than usual. The welders also go to the warehouse a lot to get a new torch.

He also found it strange that there is a large stock of wearing parts and that a pallet crate full of to be repaired torches is filled every week. A welder uses on average between 8 and 10 contact tips per day and 4 or 5 gas nozzles. With the gas nozzle, the gas distributor was also replaced in most cases. The price for a contact tip is € 0,29, the price of a gas nozzle € 1,05.

The proof of the pudding

After consulting with the purchasing department, 3 companies were invited to investigate where and how things can be improved. One such company has so much detailed information about wearing parts and torches that they are invited to do a number of tests. Three welders receive a more manageable type torch, 3 contact tips and 2 gas nozzles and a thorough instruction on how to handle these items. This should be enough for a working day of 8 hours. It is agreed with the welders that they keep the exchanged parts for later analysis.

After a week of welding, it appears that all 3 welders still use the first gas nozzle and that the gas distributor does not have to be replaced yet. One welder has just started his fourth contact tip and two welders have used five.

What is very important here is the very good cooling of the torch. This ensures that the wearing parts remain colder and therefore last longer. The quality of the copper and the wall thickness of the gas nozzle are also very influential on the tool life. For the contact tip a CuCrZr has been chosen, which is harder than the standard ECu; 160 HV instead of 110 HV at room temperature. The price of this contact tip is € 2,03. The price for the gas nozzle is € 4,08.

What is it worth?

Even without including the changeover times, the more expensive wearing parts ultimately turn out to be a cheaper option. If the cost of repairing welding errors were included, the profit would increase even further. Meanwhile, all welders have new torches and the number of repairs has gone back to 4 or 5 torches per week. The stocks of the wearing parts have also been considerably reduced. Detail, after checking the collected contact tips, it shows that some didn’t need replacing yet.

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