At the Mexican plant of fork lift frame producer NMGH, the use of ESAB OK AristoRod copper-free MAG wire is driving down costs and improving productivity.

Just five years after its launch, the advantages of ESAB's OK AristoRod copper-free welding wire are being widely recognised in a variety of industries around the world, making it a truly global product. In this article, ESAB Mexico reports on the great improvements achieved by NMHG Inc.

NMHG is one of the three core businesses of NMHG Industries, Inc., a publicly-held company with headquarters in Cleveland, Ohio.

World Leaders
NMHG designs, engineers and manufactures materials handling equipment, including warehouse trucks, counterbalanced trucks and large capacity cargo and container handling trucks. All lift trucks are marketed under the Hyster® and Yale® brand names. The company is one of the world's largest lift truck manufacturers. In addition to a worldwide distribution network of independent Hyster® and Yale® retail dealerships, NMHG operates wholly-owned dealerships in certain markets.

Today the people and facilities that make up NMHG do not support just one product line or brand, but can flexibly respond to demands of several product lines, regardless of brand. This centralised efficiency now makes them one of the industry's lowest cost producers of lift trucks and components, including replacement parts for other manufacturers' trucks.

NMHG Mexico
As part of the group restructuring plan, in 1997 the subsidiary facility NMHG Mexico, S.A. de C.V started production in Ramos Arizpe, Mexico to manufacture lower cost forklift frames for other facilities in North America. Since the start up in this plant, the company has used GMAW-P as the main welding process in state-of-the-art robotised cells.

NMHG has a team-oriented environment where employees can expand their skills and meet their career goals. Employees are encouraged to be key contributors. That is why Juan Francisco Limones, responsible for welding processes and robotic equipment in Ramos Arizpe facility, decided to initiate an investigation on how to reduce welding cost associated with unexpected equipment downtime due to poor performance of copper-coated wire. Mr. Limones found that welding cost had been affected by frequent equipment stoppage and that copper-coated wire was responsible for higher welding costs due to elevated consumption of contact tips, diffusers and liners.

ESAB Advice
Mr. Limones called in the ESAB region sales representative Ricardo Madrigal who immediately proposed the OK AristoRod 12.50 copper-free GMAW wire in Marathon Pac bulk package as a superior alternative to the competitor's copper-coated wire.

AristoRod 12.50 is a copper-free wire that, thanks to the unique ASC (Advance Surface Technology) surface treatment, allows smooth wire feeding, without friction and residuals.

Cost Savings
After an exhaustive test of OK AristoRod in several robotised welding cells, Mr. Limones gathered all the information required to compare process costs. He has estimated that the change from copper-coated to copper-free wire will generate potential cost savings up to 19% that includes cost reduction in MAG gun spare parts and downtime.

All those who know the welding process at the NMHG facility in Ramos Arizpe realise the inconvenience from the use of copper-coated wires. The gradual build-up of copper dust and flakes can cause clogging in the feed system and lead to increased spatter and poor weld finish and, eventually, to a complete breakdown of the welding process.

Regular maintenance and cleaning of the feed system is absolutely necessary to avoid feeding problems. However, this is time consuming and particularly costly as it causes downtime of the robotic welding systems. By removing the dust and flaking associated with copper, ESAB has removed the biggest contributor to the clogging of guns and liners and, with it, a major cause of production stoppages and increased cleaning schedules. In addition, greater arc stability results in less spatter, improved weld quality and finish and, consequently, leads to reduced need for weld cleaning.

Welding operators and supervisors can clearly see the advantages of ESAB OK AristoRod at every stage of the welding process:

• Low contact tip wear means fewer replacement stops.
• Consistent feedability means improved production speed.
• Lower feed force required for long distance feeding.
• Fewer maintenance stoppages due to absence of dust and flakes in liners.
• Fewer spatters due to better arc stability.
• Higher welding quality.

Juan Francisco Limones and Ricardo Madrigal are continuing with this investigation and now gathering the information to quantify the cost reduction due to improvements in welding quality and less cleaning time – two other advantages observed during application of ESAB OK AristoRod 12.50 - a product that creates savings in a global marketplace.

By Ricardo Madrigal, Sales Representative, ESAB Mexico and Juan Jose Lopez, Application Engineering Manager, ESAB Mexico.