Robotic cell halves MIG arc welding time

Pre-engineered robotic welding cells provide a cost effective system (starting at under $50,000) for SMEs, which will immediately benefit from the productivity increases offered.

A new concept from The Lincoln Electric Company is removing the usual barriers that prevent small- to mid-sized manufacturers from adding robotic welding capabilities to their operations.

With the new eCell pre-engineered robotic cell, shops now have a cost effective system (starting at under $50,000) that is easy to install.

Even small manufacturing firms will immediately benefit from the productivity increases offered by eCell and earn a quick return on investment.

Johnson and Berry Manufacturing, a 16-employee shop in L'Anse, Michigan, USA, has recently cut production time in half with the addition of the eCell dual fixed-table robotic cell.

The manufacturer of hydraulic cylinders, rollers and pins for the heavy equipment industry is using the eCell to implement a change from semiautomatic flux-cored welding to welding automation using the MIG (GMAW) process.

The result is a reduction in production time from four to five hours per job (consisting of 180 pieces) to only two hours with the eCell.

"The eCell is providing a tremendous time savings by shaving several hours off each job," said Bill Johnson, a manager at Johnson and Berry.

"With this type of productivity increase, the unit will pay for itself after only a few projects and will help us keep up with the increasing demand from our customers." With the move to robotic welding, Johnson and Berry also changed its consumable to a metal-cored wire, further increasing travel speeds.

The company is now using 0.052in Perfect Circle MetalCore wire (AWS E70-6M) on 50 lb spools from J W Harris, a recently acquired subsidiary of The Lincoln Electric Company.

This wire is used with 90% Argon/10% CO2 shielding gas.

According to Johnson, the previous semiautomatic flux-cored welding operations were yielding 50 to 75 parts per day.

In contrast, the eCell, combined with metal-cored wire is now producing 150 parts per day.

To date, the new system is not even running at full capacity! Originally, Johnson thought automation would be cost prohibitive to a small manufacturer such as Johnson and Berry.

"We had been thinking about robotics for two or three years, but assumed we would have to purchase the robot and power source separately and then hire an integrator to assemble the whole system".

"We thought this would be too costly for us".

"With the eCell, everything comes assembled as one complete package at a great price point," said Johnson.

* eCell to 'go' - in April 2005, after the purchase of the eCell had been made, Johnson and a colleague attended Lincoln's three-day robotic training class to learn basic programming and cell set up.

After the class was complete, they took the eCell 'to go' by loading it on a trailer for the 13h drive back to Michigan.

According to Johnson, the unit was simple to install once they arrived back at the shop".

""All we had to do is bolt it to the ground, run electrical and supply the cell with shielding gas and wire".

"It was then ready to produce parts," said Johnson.

The eCell is now being utilised to weld boom bushings and plates.

* eCell advantage - eCell combines the Fanuc ArcMate 100iBe robot with Lincoln Electric's Power Wave 355 M, a digitally-controlled, 350A inverter power source.

The Power Wave takes advantage of Lincoln's ArcLink communication software, a Lincoln Nextweld innovation.

ArcLink allows the system components to digitally communicate faster and more reliably than comparable analog-based systems.

The unit features the industry's fastest response time for enhanced arc starting and superior arc control".

""We were immediately impressed by the quality of the arc".

"It is easy to start and we virtually eliminated spatter, meaning no grinding of parts anymore," said Johnson".

""Previously, we were handling each bushing part three times - once to tack, a second time to weld and a third time to perform post-weld grinding".

"The eCell's fixturing is able to clamp the parts tightly into place and create the final weld".

"Our operator only handles each part one time." The Power Wave 355M comes standard with more than 60 factory-programmed waveforms optimised for a variety of materials.

Enabled through Waveform Control Technology, customers choose a pre-programmed waveform or customise that program to best fit their application.

Johnson and Berry's waveform is optimized for 1in thick steel plate.

eCell is designed to deliver high part production volumes and is capable of MIG (short arc and spray), Synergic MIG and MIG Pulse welding or flux-cored arc welding on parts which can be welded without reorientation.

It can be used to weld a variety of materials including steel, stainless steel, and aluminum.

eCell is so compact that it can be transported in a pickup truck without Air-Ride capabilities.

It can be easily lifted by a forklift to provide fast placement in the shop environment.

* Programming - after returning from the Lincoln training session, programming of the unit was handled by Johnson and Berry with the help of local Lincoln sales representative Ron Myers as well as representatives from distributor Superior Water and Welding Supply and FANUC robots.

Because each of the plates require different sized bushings, a total of 16 programs were created".

""The unit is so user friendly to program we now feel like we have always used it," said Johnson.

Welding performed by the eCell includes 1/4in fillets that are five inches long used to weld bushings to plates as well as 2in stitch welds on plates.

With the two tables, the eCell can weld while the operator unloads and loads the other side".

"* Conclusion - "Most people hear the word 'robot' and think expensive and unaffordable, but you need to also take into consideration the whole picture".

"For us, it is well worth it," said Johnson".

""We have increased capacity which enables us to pursue more work in the repair end of our business." The Lincoln Electric Company, Cleveland, Ohio, is a world leader in the design and manufacture of arc welding equipment and consumables, robotic welding systems, plasma and oxyfuel cutting equipment.

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