Since 1990 American Punch Company has made precision tooling for the structural steel industry. Their punches and dies are used worldwide for stamping structural steel components of bridges, truck frames, I-beams and other heavy-gage applications. In 2008 through an acquisition, the company expanded into lighter-gage stamping markets such as automotive, appliances and other consumer products.
The customers of American Punch, like many businesses, continuously look for ways to reduce costs and increase profits. To achieve these goals, a number of them employ lean manufacturing and other strategies that place greater demands on suppliers, like American Punch, for just-in-time deliveries. This, in turn, requires the suppliers to make smaller production runs, deliver more frequently and work within shorter turnaround times.
Adapting to these demands creates its own set of challenges, including finding ways to keep costs down despite the potential for increased labor involvement. Faced with these issues, Brian Cain, American Punch Production Engineer, began re-evaluating the company’s manufacturing processes in 2012. While the company’s high-precision punches and dies were well received by their customers, their manufacturing process was geared to standard production practices that produce hundreds of a single part, rather than smaller lots of 5,10 or 20 pieces now demanded by their customers.
“Short runs like these require multiple setups and increased attention from the machine operator which, of course, adds time and labor cost to the parts. An alternative is to make longer runs and stockpile the finished products until the customer wants them. Although we do stock a number of high-turnover parts for certain customers, adding many of these lower-volume parts ties up additional working capital, requires more floor space and increases our work-In-process. So, I began looking for ways to make these small volume runs more efficiently.
We were already using an automatic bar feeder to load material into our CNC machines, which worked well for high volume production, but not for the shorter runs our customers wanted. Each time we changed to a new part meant calling up another program on both the turning machine and the bar feeder. Clearly we needed a better solution.”
At this point Brian began to rethink how the machining process could be improved or completely re-engineered. He soon decided that the ideal solution involved the ability to gang together a family of similar parts that had a variety of lengths and characteristics, and then run them all at the same time with one setup.
When Brian attended IMTS 2012, he had a good idea of what he wanted to accomplish and asked various CNC machine tool builders and bar feeding suppliers if they had a solution. No one he spoke with could come up with a good way to run multiple parts from bar stock in a single setup. Then he visited the LNS booth and discussed his needs with Randy Lewis, LNS Systems Software & Control Manager. They discussed a relatively new product from LNS, the e-Connect Ethernet Communications System, that enables the bar feeder and CNC machine control to share data.
Because the e-Connect system and the CNC machine tool’s onboard master production schedule can talk to one another, when the lathe completes a part run, it can look at the production schedule to select the next part to be produced and send this data to the bar feeder. The bar feeder then consults its internal Part Library that stores all of the bar feeder parameters for up to 500 part programs, selects the program that matches the one chosen by the CNC machine’s master schedule, and then automatically adjusts itself to the new program.
This was exactly the solution Brian was looking for. “I learned that we were on the ground floor of this kind of data sharing that’s now becoming more widespread. At that time, the CNC machines we had were not yet equipped to share data with the bar feeder, so LNS worked with our machine tool supplier, Ellison, and the OEM to enable the lathe’s control to communicate with the LNS e-Connect system.”
In this application the e-Connect system resides in the LNS Quick Load Servo 80 S2 spindle-length, all-electric, servo controlled, fully automatic bar feeder that loads 14” to 63” bars (not to exceed spindle length) with diameters ranging from ¼” to 3-1/8”. The American Punch machine operator loads the bar feeder with 1-1/2” tool steel bar stock and runs a macro program that enables the lathe control and bar feeder to change from one family of parts to another on the fly.
A typical setup would include loading the appropriate diameter bar stock to make various quantities of different length parts. For example, using 1-1/2” diameter bars to produce 50 parts 2.500” long, 10 parts 3.025” long, 75 parts 3.500” long, and so on. The parts may vary in form, as well. According to Brian, “It’s a huge advantage to take just a brief time in the morning to setup the run, load the bar stock and then walk away while it makes a long run of a variety of parts. This means we can run unattended and even lights-out. Previously the machine operator had to load the bars and stand by the machine as it made a small batch of parts and then reset the CNC machine and the bar feeder to make the next size part. Now the operator is free to tend additional work cells and perform other tasks.”
Today, with 4 work cells using the LNS e-Connect system and bar feeders, American Punch runs over 300,000 parts each month and is in the process of adding additional capacity to meet customer demands. The newest work cell consists of an LNS Quick Load Servo 80 S2 bar feeder loading bar stock into a Doosan Puma 2100SY turning center with milling, drilling and tapping capabilities. In addition to interfacing with the LNS bar feeder, the CNC machine also communicates with a programmable, high-pressure system to apply the precise amount of coolant for each machining operation.
“These work cells have made a significant improvement in our cost-per-part through unattended operation and by adding a labor-free overnight shift. Equally important has been the improvement in our ability to meet our customers’ delivery demands. Without the e-Connect system we were constantly struggling to stay on top of orders. Now we not only solved the time-to-delivery issue, we’ve expanded our capacity to take on additional work.”
American Punch prides itself on implementing new technologies. When we looked for this solution back in 2012, I don’t think anyone was talking about the Industrial Internet of Things, but e-Connect is certainly part of that trend. Since then we’ve built a strong relationship with LNS and now have 4 e-Connect enabled work cells with LNS bar feeders. Their support over the years has been very good. If we have a question I can pick up the phone and get the answers I need. The LNS field technicians are knowledgeable about the Ethernet systems and work with the various OEMs we have machines from.”
Although not presently an issue for American Punch, another benefit of the e-Connect system is reduced material waste. In addition to storing the bar feeder parameters for each of the part programs, e-Connect tracks material usage and communicates this information to the machine tool. The master schedule looks at the amount of available material and the lengths of parts in the production queue to determine if there is enough material to run the required quantity of a particular part. If so, it runs the complete part run. If there is not enough material for the entire run, the system determines the length of any remnant, calls up the next part in the schedule that fits the remaining stock, and the lathe and bar feeder automatically adjust to make the new part. Once the bar is used up, the bar feeder loads the next bar and the system repeats the process until it makes all of the scheduled parts.