Various market factors and economic conditions now make retrofitting machine tools a viable strategy for improving machining performance, a realization that has set in for operators of large-scale OEM metalworking departments as well as smaller moldmaking operations, tool-and-die producers, and contract part manufacturers.
That’s the message from Tom Curfiss, the retrofit business development manager for Siemens. “Today’s business climate has combined with economic factors involved in the manufacture of control packages to create an ideal atmosphere for retrofit,” he explained. “Our company has long been involved in the upgrade of large gantry mills for aerospace production, for example. But today, it’s just as likely you’ll find our Retrofit Solution Partners outfitting a 3-axis mill or even a basic lathe with a new entry-level or mid-range CNC, motor and drive package.
“And, the best news for the job shop,” he indicated, “ is that this work can now be done at a price point comparable to just the cost of the CNC a decade ago, owing to economies of scale in the manufacture of these control packages.”
Siemens has 17 Retrofit Solution Partners under contract in the U.S. These companies work closely with Siemens to understand more fully the possibilities of retrofitting machines with Sinumerik CNC, and to provide complete services for the installation and refurbishment of the CNC machine.
These partner firms for the Machine Tool Systems business at Siemens must have a demonstrated ability to work on CNC, PLC, servo motor, digital drive, and all accompanying peripheral products, plus have a proficiency in the development of software packages related to PLC and CNC applications. Then, every partner commits to a round of training sessions on Sinumerik controls and is required to keep at least two Siemens-trained engineers on staff at all times, according to Curfiss.
The selection of Solution Partners is not based on geography, and several have proven expertise in the field working on particular types or brands of machine tools. The selection process for the appropriate partner takes many factors into consideration, Curfiss said. “We have partners who specialize in 5-axis machines, others who have expertise in a certain industry such as aerospace or medical, and still others who have their greatest strength in a particular area of the country. Depending on the job specifics and the logistic costs involved, we work hard to match the right partner to the customer’s needs.”
Evaluating Appreciable Differences
Typically, Curfiss continued, the tipping point on a retrofit job is 60% of the price of a new machine. However, he also pointed out that many machines have outdated controls, although they still perform adequately in the shop or production department.
“The challenge, when we do our onsite machine evaluation, is to determine whether a retrofit will make an appreciable difference in the performance of the machine, as other factors in the mechanics of the iron might make a retrofit impractical,” he said.
Curfiss went on to note that today’s control technology is evolving at a very rapid rate, making some equipment that went out of production just 10 years ago less than optimum in contributing to maximum machine tool performance. “Running machine tools with 20-year-old technology today will simply not keep a shop as competitive as it needs to be,” he stated.
Tom Curfiss has had experience with “old iron” in the field: his background in machine tools spans over 40 years. “A lot of people think their old iron is just impossible to keep running, even with a retrofit, but we’re able to make the old equipment run better than it did when it was new, quite often,” he said. He noted these achievements result from faster control processors, improved motor and drive technology, even more accurate and responsive encoders and other machine status sensing devices. On a practical note, Curfiss also remarked, “You cannot, however, fix a broken leg with a bandage, so the machine evaluation needs to be very comprehensive.”
In the end, Tom Curfiss suggested, both the large production departments and the job shops need to have regular assessments completed on their prototype and production machine tools to determine if a retrofit might be in order.
“The savings can be substantial, compared to purchasing new machines, because it’s not just a matter of the dollars saved at the outset,” he said. “It’s also the long-term production improvements that inevitably lead to even greater profit for the job shop or OEM.”
