The inherent flexibility of the Swiss-type machine tool configuration has been greatly enhanced with the application of CNC servomotor actuation in the place of mechanical cams. This trend continues with the development of CAD/CAM programming software that makes the transfer from design to tool path ever more efficient and user friendly.
Shops of many stripes have seen these developments and jumped on the bandwagon to take advantage of benefits they provide such as high production rates, close tolerance capability and the ability to produce complex geometries complete using a single handling of the workpiece bar or blank. Historically, the Swiss-type machine has been primarily applied in “screw machine” shops. However, its increased capability as well as application of CNC that have led to a branching out of this historically niched technology into other types of production environments.
The trend to non-traditional machining led us to visit Economy Spring, a MW Industries Company. Economy Spring is a contract shop located in Southington, Connecticut. It was founded in the mid-1970s and today employs 190 people at its Connecticut location. Economy Spring is one of 22 companies that comprise MW Industries based in Rosemont, Illinois, which collectively serves the spring, fastener, stamping and precision metal components industries.
Using a laser cutting head on a Swiss-type machine enables Economy Spring to provide additional capabilities to its medical customers.
In addition to its spring making equipment, Economy Spring currently uses two Swiss-type machines from Marubini Citizen-Cincom. Each machine is equipped with a L2000 modular laser system in which the laser cutting head resides in the machine’s cutting zone. It’s a process departure that allows Economy Spring to perform operations that would require secondary or even tertiary production steps beyond its traditional niche.
As the company name indicates, Economy Spring is a spring manufacturer. Springs, wireforms, and stampings of many sizes and shapes come off the shop floor’s banks of four-square machines and other wire processing technology. The two metalcutting Swiss machines look a little lonely in this sea of metal bending equipment, but they are serving a purpose as an investment in the company’s future.
Much of the work that Economy Spring does supplies the medical device industry. It products are critical to the operation of instruments that are applied across the medical industry and manufactured using components that the company makes.
Economy Spring’s primary product has been manufacturing numerous types of springs, stamping and wireforms using four-square and other metal fabricating equipment.
Like many shops that serve the medical industry, Economy Spring is searching for ways to provide more processes and hence more products to the customer base that it serves. The pharmaceutical and medical device OEMs and contract manufacturers are looking to consolidate the number of suppliers with whom they interface.
“In one example,” says Tim Thompson, senior VP and general manager, “a major medical equipment OEM is actively trying to move from 52,000 suppliers to a target of 10,000.” Shops such as Economy Spring want to be among those 10,000. To that end, the thinking behind the shop’s application of laser Swiss technology is to enable it go after new work that has been beyond its traditional niche.
Learning by Doing
The original impetus that led Economy Spring to look at laser cutting and eventually invest in the technology as applied on a Swiss machine came from one of its customers. According to Dan Bartlett, engineering manager for Economy Spring, “We had a customer that wanted us to produce a 0.063-inch hole in a stainless-steel tube used in surgery. We tried piercing it first using a secondary machine, but the results were not satisfactory.”
“We contracted with a nearby vendor that had a Citizen laser Swiss machine to see if they could do the job. They started making the part for us,” says Nick Coburn, project engineer for Economy Spring. “We were trying to make these parts using conventional techniques, which weren’t working well for this application. After seeing the capabilities that our vendor was experiencing using a laser (in combination with Swiss cutting), it got the wheels turning for us to see what else that technology might bring to our shop.”
The shop’s first laser Swiss machine, a Citizen L220 Type 8, was installed in 2016. Development of laser cutting processes continues to open new avenues of business for the shop.
Economy Spring took delivery of its first Citizen machine in April 2016. It was equipped with a laser attachment, and the company began developing its in-house processes to make the job they had previously sent out.
In fact, they now make a similar part using stainless steel tube stock that has an 0.020-inch OD and a 0.01-inch ID in which they are drilling a 0.007-inch hole. The laser has opened up new opportunities for the shop. Demand was such that Economy Spring took delivery of its second machine a year later.
The increased machining capability that the new machines bring to Economy Spring is freeing up designers of medical devices to design using specifications that weren’t possible before. “As the medical device community is learning that there are methods to produce fine holes as well as other types of cuts we are able to produce using the laser, they are seeking out companies with those capabilities,” Mr. Coburn says. “Their designers are advancing the capabilities of their instruments in step with our industry’s ability to manufacture the designs.”
Working With the Laser Swiss Machine
In our interview at Economy Spring was Dale Akerley, the department leader for Swiss applications and has a front row seat for the company’s development of its processes involving the use of the machine-mounted laser.
“A benefit we see from the laser over conventional cutting tools,” he says, “is the laser cuts without wear. Conventional cutting tools wear over time and require compensation as they wear. Moreover, they exert cutting forces and often leave burrs on the workpiece. The laser does none of these things. With the correct gas, the HAZ (heat affected zone) associated with laser cutting can be managed. Any dross left around the cutting area comes off in the cleaning process using an acid dip and ultrasonic parts cleaner.”
Production across the Citizen machines is set up like a job shop. They are not dedicated to a single job, rather the quick change-over of the laser makes small lot sizes practical.
In the shop, one of the Citizen machines is used for prototype and process development work. According to Mr. Coburn, “It can take as much as two years for a manufacturing process to become certified in the medical industry. In the meantime, those jobs that are already certified can be run in production on the second machine.” Production for Economy Spring is generally in the 10,000 to 30,000 lot size range and are made to existing orders.
Economy Spring’s laser team, (left to right) Dan Barlett, Nick Coburn and Dan Akerley, are driving development of the laser process technology on the shop floor.
Economy Spring sees its laser cutting capability as a value-added service for its customers and rightly so. The company’s efforts at soliciting work for the machines focuses on that capability in large part because the process is still relatively new to the industry. However, it is also working to integrate the metalcutting capability of the Swiss machine in concert with the laser.
The primary variables for part production on its Citizens include holding the part and ejecting the part. Beyond that, Economy Spring uses DP Technology’s Esprit software to program the machines. Toolpath generation is relatively straightforward using the software’s inherent Swiss type toolpath generation.
To make sure that the Swiss machining and laser cutting were compatible, Mr. Akerley, and other team members, attended a programming class in North Carolina to learn how to integrate the laser cutting operations into DP’s Swiss machining programming software to make the system seamless. This entailed taking the M and G codes for the laser, which were considered “add-ons” in the CNC and ensuring they were incorporated into the Esprit software. “It was a first for both parties,” he says.
What Can the Laser Do?
The initial application of the laser for Economy Spring was to drill accurate, relatively small holes. Having mastered that, the company continued process development using the cutting ability of the laser to generate slots, spirals, helical shapes, widows and other complex shapes.
Cutting small holes accurately and without burrs is an examples of an operation that the laser machine has enabled Economy Spring to perform.
The basic laser is a fiber optic design and uses a 50-micron delivery fiber with kerf widths of 20 microns. Interpolating the main and secondary spindle’s C-axes, and having the laser set at its correct focal length and depth of cut, opens up virtually any geometric shape for production.
Economy Spring collaborates with its customers to develop the optimal use of the laser’s capabilities for the job that needs to be done. According to Mr. Coburn, “They will present us with a drawing that contains an idea, which represents what they want. We then provide them with other options that make the job in ways the customer may not have considered. It’s a two-way communication street.”
Citizen says its laser Swiss machine is able to cut and weld as well as laser marked parts that are processed on its machines. Marubeni has laser welding available on the machine as well. It is probably only a matter of time before welding and marking becomes part of Economy Spring’s laser tool kit.
About the Lasers
The first machine that Economy Spring received is a L220 Type 8 with a 400W laser attachment. This Swiss machine model has eight axes of motion under CNC. Mounted on the tool slide, its laser is fed into the workpiece at a right angle in the cross-slide position. The Type 8 can cut tube thicknesses of 0.0625 inch with a kerf width of 0.0015 inches.
For its second machine, and with some experience under the belt, Economy opted for a L220 Type 12 machine (cable of 10-axes of under CNC) with a more powerful laser attachment. Its laser can generate up to 3,000W of power and is qualified to cut 0.125-inch-thick tube stock and generates a 0.0035-inch kerf width. The second laser is mounted on the machine’s B axis for cuts that require angularity.
To survive in the cutting environment inside the machine tool, the laser head assembly is completely water tight. In some applications, use of high pressure coolant is encouraged and is available as an option on the machine. This coolant can be directed into the workpiece and through the tubing from an automatic bar loader.
The Citizen laser attachments have available a fine X-Y beam alignment feature that uses an integrated camera to position the laser nozzle precisely at the start point of the cut. Both of the laser units used by Economy Spring on its Marubeni Citizen machines are made by IPG Photonics, a U.S.-based manufacturer of fiber optic lasers. The units are modular and can be installed in various new machine models as well as retrofitted on some existing machines.
All this may beg the question, is Economy Spring a technology pioneer? How risky is it for a metal bending shop to jump into seemingly advanced technology such as laser cutting on a Swiss-type machine tool?
The answer to these questions lead to another question: How risky is it not to get into this type of technology? With the backing of its parent company, Economy Spring is developing a skill set base that can offer process capabilities that are not commonly available and that shows signs of being marketable. As the medical industry seeks to consolidate its supplier base, companies that can move ahead of the pack with new ways to perform operations and produce parts creatively and competitively stand a good chance of making the cut.
The team that Economy Spring has assembled to develop its laser processing capability is enjoying the challenge of making this new technology work. For an engineer, it’s a green-field opportunity that doesn’t happen every day. As the laser development team says, “We have worlds to conquer.”
This video features Marubeni Citizen-Cincom's L2000 laser system for use on its Citizen and Miyano Machines.
For more information from Economy Spring, call 860-621-7358 or visit mw-ind.com.