Automate and Separate

Automate and Separate

December 11, 2013 12:07:23 PM

At TNT EDM Inc, success hinges on working smarter, not working harder. The company is focused on lights-out production. Most, if not all of its machinists run multiple machines simultaneously, up to ten in some cases.

Automation plays a critical role in TNT’s “working smarter” game plan, as does the way the shop arranges its machines.

“We have changed the way we approach jobs. For example, with EDMs, we realized that jobs typically involve multiples – either multiple pieces or multiple burn areas. By incorporating robots, we can accomplish both,” explained Tom Mullen, president and owner of TNT EDM.



“Instead of running one or two pieces of a job on a machine, we may run 50, and change them using a robot. With large parts requiring multiple burns, we always try to do them all in one setup,” he says.


EDM automation at TNT consists of robots utilizing tool/electrode changers, along with workpiece and pallet changers. A large portion of such automation can be found tending the shop’s Mitsubishi sinker and wire EDMs.

“When we look at a job, we think of how we can automate it. Even if it’s only four or five parts, we’ll try to automate the job by setting it up on pallets, or, if possible, fixture all the parts on one magnet to avoid having to re-fixture parts,” Mullen said. 

But the shop doesn’t automate jobs just to take the operator out of the equation. Automating is part of working smarter, and it doesn’t always involve robotics. On one of the shop’s jobs, an operator was running two parts simultaneously. They re-thought the job and built a fixture that holds 10 pieces. The operator now runs four of these fixtures at a time – a total of 40 pieces. This thought process enhanced their productivity and allowed them to offer a cost reduction to customers.

Mullen said it’s that kind of thinking that continues to make the shop competitive. But, he mentioned that once an EDM is automated and basically runs around the clock, the only way to increase capacity is to add more machines.

TNT started out as an EDM house doing strictly mold work, but after about five years, Mullen realized that the only way to grow the business was to expand its capabilities beyond EDM. There weren’t a lot of customers that wanted the shop to do just the EDM work on a job.

And while TNT is still a premiere EDM house, it now has more milling, turning, grinding and inspection machines than EDM equipment. These added capabilities helped the shop expand into the aerospace/defense, land-based power generation and medical industries.


“If we hadn’t taken the gamble to buy the equipment we did about seven years ago, we’d be dead in the water as far as winning new work is concerned. We can now go after the parts that are complex, hard to program and difficult to process. We can’t just machine square blocks and expect to be competitive,” said Mullen.

Within TNT, there are, for the most part, 13 shops within a shop, and types of machines are separated and segregated into individual rooms. The sinker EDM room is separate from the hardmilling room, as is the wire EDM room separate from the green-machining room and the grinding room. While this may not be how most shops organize machines, Mullen said he gets a lot more output from his arrangement.


His logic is “do what you do best and forget the rest.” For example, the guys that run the wire-EDM room program and run only wire EDMs. They aren’t operating sinker EDMs or milling graphite for electrodes.

“All the different machines are in their own rooms, and the work comes to them. At one time we had six similar types of EDMs located in six different areas of the shop, with five separate operators running them. Now, we have 15 of the same type of EDMs in one room, and two people keep them all working,” explained Mullen.

The shop blasts through much more work with one guy running 10 machines as opposed to the same guy running one wire EDM and one sinker EDM.“For us, and I believe for the overall job shop environment, the cell concept does not work. Cells mean you have to have one guy that knows how to run, for example, an EDM, a milling machine, and maybe a grinder. Being able to effectively process all of those operations is just too much,” Mullen said.

With TNT’s machine arrangement, parts that require operations on different types of machines travel from one room to the next by way of carts. And whether it’s five parts or 100 parts, all the parts of a job stay together and are not scattered around the shop at different machine locations. Parts move to each process area, get signed off upon completion, then move to the next process area, repeating the sequence until completed.

Mullen said there is nothing better than a visual – all the parts for a job sitting on a table – to find out exactly what stage a job is at in production. And, most of the shop’s parts weigh 5-20 lbs, so transporting them around the shop is no big deal.

TNT will continue to evolve, increasing its capabilities and flexibility to match the constantly changing demands of its customers and markets.

“We started out with only EDM, then added our 5-axis and other milling machines. The future will bring an investment in waterjet and laser cutting machines, adding capabilities that will allow us to enter new markets and continue to grow our business,” said Mullen.


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