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Shop Solutions: Automating Workholding Production

 

Entrepreneurial thinking means taking entrepreneurial risks. For workholding specialist Allmatic (Unterthingau, Germany), a member of the Jakob Group, that meant making a decision about installing a new flexible manufacturing system (FMS) and deciding which new machining centers to invest in that would allow it to meet the production challenges for its workholding products.

Allmatic is a manufacturer of workholding clamping units that are available in standard versions with different jaw widths. Product lines include the Titan 125 vises, T-Rex vises, Monobloc Multi vises, and the two most recently introduced models, the Duo Plus 125 vise and Centro Gripp 125 vise. The company’s products are subject to wide fluctuation in demand. For example, demand for one model can increase by as much as 40% during one month only to drop dramatically during the next two months. Production lot sizes typically vary from 10 to 200 pieces per order.

According to Allmatic CEO Bernhard Roesch, it would have been a simple job to replace the two old StarragHeckert machining centers with two new ones. But he is convinced that "such a decision would not really have brought us forward." The decision wasn’t just about replacing the old machines, it was about investing for the future, Roesch believes.Allmatic has installed a flexible manufacturing system featuring a Liebherr PHS 1500-L pallet handling system for machining its workholding products with two StarragHeckert HEC 500 HMCs

The goals for the new FMS were to eliminate setup times, speed response times to match order fluctuations, lower lead times, increase capacity, and even bring in-house some work that had been outsourced. The FMS consists of two StarragHeckert HEC 500 HMCs with a total of 56 630-mm pallets and a pallet-handling system. Pallets use Allmatic’s own Monobloc or tombstone workholding and a PHS 1500-L pallet handling system from Liebherr Verzahntechnik GmbH (Kempten, Germany; Liebherr Automation, Saline, MI). The system is controlled by a PCS cell controller from software provider Soflex with tool-setting by Kelch.

"We wanted to reduce setup times to a minimum with the ability to run unmanned production," explains Herbert Mayr, Allmatic production manager. Setup times proved to be the main bottleneck when fast response times and flexible capacity adjustments were needed to meet demand forecasts by production planners based on sales generated. "We were happy if we could submit a fairly stable weekly production forecast," says Mayr. "If demand for one product then suddenly increased, production had to buckle down and throughput times would go up as a result."

A flexible manufacturing strategy, while minimizing setup times, was still not enough to satisfy all of the company’s production requirements. To handle order volumes, a three-shift operation was deemed necessary. The third shift and a future planned weekend shift were intended to run without operators. In fact, Allmatic had previously had bad experiences with manned night shifts when both quality and output of products suffered. Choosing Liebherr’s automation solution to feed the two machines relieved the operator of handling tasks and allowed higher machine utilization. This was not a problem, because Liebherr technology had demonstrated its capabilities in developing automation solutions for both high-volume production and flexible pallet handling systems for single-piece and small-lot series production.

The economics of the new system proved especially favorable when the elimination of setup times is considered. For this reason, the 56 pallets are equipped with flexible clamping units so that the entire part range including all product variations can be clamped. The operator only needs to remove the finished parts and clamp new ones. The approach utilizes tombstone-type fixturing with monobloc-type workholding combined with vises and high-pressure clamps, all from Allmatic. Setup time is completely eliminated, and up to eight parts can be mechanically clamped at each tombstone.

"We believe that a system like this can only be operated cost-effectively if you build a proper environment for it," says Roesch. With only one person needed per shift, qualified technicians can be used to operate the system. The high level of employee qualification has to do with the fact that the operator is responsible for the entire area of operation. Operators determine at the beginning of each week which parts will be machined at exactly what time. In addition, their responsibilities also include tool preparation, tool deployment, raw material supply, and performing finished-part quality control.

If the operator is the heart of the system, the Soflex cell controller is the brain. The cell controller stores all NC programs for the two machining centers. When the operator clamps on a part, he confirms this at the cell controller by pushing a button. Now the cell controller knows exactly the location of each clamped part, and which NC program is needed. The system also recognizes which tools from the tool magazines are required, and whether remaining tool life is adequate to complete the part. In the event of a tool failure during unmanned operation, the part is sorted out and processing continues with parts for which all required tools are still available. The Soflex cell controller uses standardized software modules, which allow a straightforward implementation of interfaces to CAM and a production planning system.

Implementation of the flexible manufacturing system lasted 15 months and required an investment of $2.7 million. In addition to economic gains, including lead-time reduction, high utilization of machining centers, and unmanned third and weekend shifts, increased capacity allowed 50% of previously outsourced parts to be made in-house again, increasing flexibility and reducing stock levels.

"If we now know which parts we need tomorrow, we just hit the button by 4 pm and the next morning, the parts are ready. It doesn’t matter whether we need 50 parts tomorrow and 150 parts the following day. We now have everything under control," Mayr concludes. ME

 

For more information from Liebherr Automation Systems, go to www.liebherr-us.com, or phone 734-429-7225.

 

 

Improving Laser Parts Production

When Trumpf Inc. (Farmington, CT) looked for a better way to produce high-precision components for its lasers and fabricating machines, the company selected a flexible solution that would yield maximum accuracy, reduce time-to-part, and increase material cost savings. The solution was found in two five-axis universal machining centers equipped with twin rotating pallets from DMG / Mori Seiki (Hoffman Estates, IL), and an automated loading system from Fastems LLC (West Chester, OH). CNC controls and drives are supplied by Siemens Energy and Automation (Elk Grove Village, IL). 

Trumpf designs and builds over 30 models of metal-processing machinery at its Farmington campus, where it also maintains a customer training center, an R&D facility, and a demonstration showroom for its Nd:YAG and CO² laser capabilities. The company produces virtually all of its laser and fabricating machine metal parts in-house, affording it quality control, fast response, and the ability to customize equipment and to contain overall cost. It’s part of what Trumpf president and CEO Rolf Biekert terms "unabhaengigkeit," the German word implying self-sufficiency and self-reliance.

For many of the components, which range in material composition from mild tool steels to high-purity stainless, machining was previously performed on a series of HMCs and a stand-alone five-axis milling machine at Trumpf’s manufacturing facility. "The implementation of the two five-axis machines, working in concert with the pallet-changer system from Fastems, allowed us to replace the HMCs with this newer technology, transfer 70% of the work from the stand-alone mill, and overall keep our production running in a more streamlined manner," explains Kai Moellendorf, director of manufacturing.

Steel and aluminum housings and structures are machined on the two DMC 100 U duoBlock machining centers. A twin-pallet system on each machine allows loading and unloading of a fixtured workpiece by the Fastems automated system while machining is under way. Each machine is equipped with a custom 60-position HSK-A63 toolchanger, and the tools are chip-encoded via an off-line preset system. An additional 240-position toolstation is accessed by a robot that delivers each tool in sequence to the machine. Machining a laser resonator frame at Trumpf on a DMC 100 U duoBlock five-axis machining center with Sinumerik 840D powerline CNC and Simodrive 611 D drive package reduced cutting time by 28%

Controlling all axes, tool-change, and pallet movements on each machining center is a Siemens Sinumerik 840D Powerline CNC with Simodrive 611D drive package. The CPU has a video link to the operator terminal. Peter Hafner, components manager, says that this arrangement has resulted in substantial savings in time and labor for his department. The tool ID chips are read by a CCD camera prior to entering the machine magazine, so there’s that additional safeguard against the wrong tool entering the work area. "We strive to take every variable out of the machining center to keep it running at maximum efficiency," Hafner notes. The company’s goal is 24/7 operation of these machining centers within one year, and Hafner is optimistic that goal is realizable.

On one laser resonator frame, eight holes are required with true position of 0.0016" (0.041 mm) with a 0.39" (10-mm) H7 diam and 0.39" (10-mm) depth that must be held. Also, the parallelism and perpendicularity on eight surfaces of the frame must be within a 0.0008" (0.02-mm) tolerance. Accuracy is paramount for this welded steel frame, which holds a laser resonator in position. Trumpf manufacturing engineer Edin Meskic confirms the DMG / Mori Seiki machine is maintaining the tolerances at better than twice that requirement. Plus, the overall machining time has been reduced by 45 min per piece, a 28% improvement.

Typically, parts are designed by Trumpf engineers in SolidWorks, then fed into the machining centers via Ethernet communications protocol. The CNC utilizes proprietary DMG /Mori Seiki interface software as well as the Siemens ShopMill software suite, with Ethernet communication of all machine condition status to the internal Trumpf server for production monitoring. Throughout the facility, performance data are displayed for all to see. According to Moellendorf, "This gives everyone here a sense of accomplishment when we meet or exceed our goals, plus it provides the incentive for all of us to maintain those levels of productivity. We all take pride in keeping the curves on the upswing."

At the outset of the evaluative process that led to the purchase of these machining centers, the decision was made to purchase medium-sized units. Peter Hafner says, "We established a questionnaire, based on technology, engineering assistance, sales support, training, and other factors. We’d worked with DMG in the US previously, and they were deemed the most capable of handling our complex requirements, as the machine builder. Control was the next issue. Our emphasis there was on quality, functionality, expandability, and price, of course. With five-axis, spindle, and ancillary motion control involved, the CNC and drive package needed to be very adaptable to our numerous short runs, varying sizes, extremely tight tolerances, and expansive toolhandling requirements.

"Plus, our internal machine communications program, as part of our Synchro policy of lean manufacturing and continuous process improvement, demanded the most sophisticated control data transmission capabilities be onboard. Finally, the extra demand of integrating the Fastems pallet-changing system was critical, both in terms of speed and reliable delivery of the correct workpieces to the two machining centers. When all these factors were considered, plus their status as our existing OE supplier for controls, the choice of the Siemens CNC and drives was relatively easy."

Trumpf utilizes the Kanban system of time management to further maximize the efficiency of component movement through their own manufacturing process. As parts are required, the shop orders are fed directly to the appropriate machine-tool department equipment and its onboard CNC. The workpiece and proper tooling are called up and the process can begin at a specified time. Furthermore, the company’s internal Synchro system of lean manufacturing and continuous process improvement has added even greater efficiencies to the overall production scenario at this company. As Kai Moellendorf explains, "Our own ERP system tells us about our productivity, and there is an ongoing evaluation of leading indicators within our operation to maintain a constantly updated status on performance. It pushes us and we respond."

DMG / Mori Seiki wrote the program to integrate the pallet system with the two machining centers, working in conjunction with Siemens and Omron, the control component supplier on the Fastems system.

Trumpf also operates a full department of Index lathes to produce other components, and these machines are also equipped with Siemens 840D CNCs and 611D drive packages. Here, the rotationally symmetrical stainless parts for the laser beam delivery system are produced. Troubleshooting on all the machines in this department, as well as the machining centers, is performed through remote diagnostics from an IP address onboard.

Siemens CNCs are used exclusively on the Trumpf metalworking and laser machines. This partnership extends worldwide, as the control supplier and machine builder have joined together to develop operating interfaces, both at their headquarters in Germany, in the US, and at other mutual corporate locations around the world. "We utilize Siemens CNCs as our standard platform, whether for laser, punch, combination, forming, welding, or other Trumpf machines," says Michael Reuster, chief of software engineering for the company. Peter Hafner adds that the Siemens CNC processes the metalcutting commands on the DMG / Mori Seiki machining centers with the same speed and precision as it does the laser intensity, flying optics, punching, nesting, and other program commands on the Trumpf lasers and other metalforming machines. "We have partnered with DMG and Siemens over the years and that’s made us a better company, that’s a fact," concludes Kai Moellendorf. ME

 

For more information from Siemens, go to www.usa.siemens.com/cnc, or phone 847-640-1595; on DMG / Mori Seiki USA, go to www.dmgmoriseikiusa.com, or phone 847-593-5400; on Fastems LLC, go to www.fastems.com, or phone 513-779-4614.

 

 

 

Giving Parts Inventory A Lift

Making the switch from paper-based fulfillment to automated vertical lift modules (VLM) provided a significant savings in space and cost for M/D Totco’s 10,000-SKU multipurpose parts warehouse, which serves its manufacturing and distribution operations. M/D Totco, a division of the National Oilwell Varco (NOV) family of companies, wholesales, leases, and rents oilfield equipment, and manufactures nonlaboratory scales and balances, electronic coils and transformers, process control instruments and oil/gas field machinery. Results include increased order accuracy from 98 to 99.5%, manhours reduced by 15%, and warehouse footprint reduced by 33%, freeing more than 16,000 ft² (1486 m²) for needed manufacturing space.

M/D Totco maintains a fully-integrated manufacturing facility with machining, fabrication, welding, and laser capabilities for the production of electronic, mechanical, hydraulic, and pneumatic assemblies, as well as specialty sensors and CVD (control vertical drift) equipment for down-hole azimuth and direction drilling. The company is a leading provider of integrated systems that provide real-time drilling information and control.

Its business is split between direct equipment sales to oil and drilling companies and equipment rentals to field stores that install the equipment on drilling rigs under rent or lease contracts. Consequently, the rental equipment eventually comes back into the plant to be serviced.

For M/D Totco, the need for more manufacturing space was critical. After 25 years in the same location, its 250,000 ft² (23,226 m²) manufacturing and distribution facility in Cedar Park, TX, was running out of space. Expanding the building horizontally was not an option, as site constraints were an issue.

M/D Totco decided to upgrade several areas of its plant, including its main parts warehouse, manufacturing tool crib, and electronics center warehouse.

The new shuttled vertical lift modules (VLM) that were designed, built, and installed by Remstar International (Westbrook, ME) not only solved the space problem, they also increased inventory accuracy and cut inventory labor hours allowing workers to be redeployed to other areas of the plant.

Supporting the plant is a 10,000-SKU, formerly 50,000 ft² (4645-m²) parts warehouse that is dedicated just for inventory. Eighty percent is used for kitting workorders in manufacturing, and 20% for replacement parts shipped to its customers. Circuit boards, electronic modules, media discs, rubber gaskets, epoxies, O-rings, and PLCs are some of the $23 million in inventory that the warehouse manages. The plant’s inventory is extremely comprehensive; it still stocks products from the 1950s and 1960s, hydraulic and pneumatic technologies used in oil wells.

Until recently, these parts were inventoried on shelved racking. When a part or kit order was received on a paper printout, the worker would pick by location with the aid of a ladder or cherry picker and load the part onto a cart. When the order was complete, the cart was taken to the manufacturing cell or to a staging area in shipping. This was a time-consuming and labor-intensive process considering the warehouse handles 30,000 individual part-picks per month.

The tool crib's 2000 ft2 area has been reduced down to 300 ft2 by using the Remstar VLMAnother area of inventory for the plant is the manufacturing toolcrib located on the plant floor, handling thousands of tools and consumables needed for manufacturing, such as carbide drill bits, tool fixtures, safety equipment, and gages. The toolcrib was operated manually, and experienced costly problems with poor tracking of tools resulting in lost equipment.

The third inventory area of the plant is the electronics center warehouse, also on the plant floor, which services the electronics assembly manufacturing cells. This facility inventories spools of wire, approximately 75 part numbers, some spools as large as 2' (0.6 m) in diameter and thousands of linear feet long. Wire was inventoried on rack shelving and the area was unmanned. When an order required that wire needed to be pulled from inventory, workers would need to sift through piles of wire spools to get to the items they needed, taking typically 30 min to fill their orders.

"We liked the idea of vertical storage for our inventory," says Wilton Hockaday, inventory control & warehouse manager. "Reducing our inventory floor space to gain more manufacturing room was very attractive to us. We selected Remstar International to design, build, and install six shuttled vertical lift modules in the plant. Four VLMs were installed in the main warehouse. Another was put into the tool crib area, and still another VLM was installed in the electronics center."

The VLMs contain a vertical series of shuttled trays—each 34" (863.6-mm) deep × 8' (2.44-m) wide—within a 30' (9.14-m) high vertical housing. The units reach almost to the 32' (9.75-m) ceiling of the plant. Each tray can hold up to 1100 lb (499 kg) of parts. The VLMs have a much denser storage capacity than our shelving racks.

The shuttled vertical lift modules are equipped with the latest put-to-light and pick-to-light technology. A Transaction Information Center (TIC) light bar that runs across the front of the unit and directs the operator to the exact location of the part to be picked, and displays the quantity to be picked as well as the part number.

When an order for an item is received in the VLM zone, the worker scans its identification barcode, and the VLM shuttles move to deliver the item to the operator. The TIC lights on the outside of the VLM direct the operator to the precise location to make the pick, and specify the quantity of pieces to be picked. The operator picks the part as directed by the TIC and places it in the cart. He then picks the next part presented by the VLM, and this is repeated until all parts have been picked for that order. When complete, the order is delivered to the originating manufacturing cell or routed to a staging area in shipping.

Most part orders are initiated 48–72 hr prior to being picked, and are assigned an identifying barcode by the warehouse. But when a part is needed on a priority basis for manufacturing or shipment, the VLMs interface with the company’s MRP (Material Response Planning) system. The rush order is entered into the MRP system in the warehouse, and the VLMs are automatically instructed to present the part for picking. The light bar then displays which part, where the part is located in the shuttle, and how many to pick. The company’s MRP is an older system, but the Remstar VLMs were able to interface with it successfully.

The VLM in the tool crib area is used to store, check in, and check out tools for the manufacturing floor and is interfaced with CribMaster software. Workers submit requests for tools to the crib attendant, who then pulls the tools from the VLM and delivers them to the manufacturing cell. The returned items are then checked back in by the tool crib worker once returned by the cell. The tool crib now always has a record of who used what tool, and when. The system knows what tool was used on which job, enabling better supervised point-of-use distribution to minimize tool losses.

"With the installation of the four VLMs in the main parts warehouse, 33% of its floor space, or 16,000 ft² [1486.45 m²], has been freed up for manufacturing," says Hockaday. "This represents only 40% of our inventory, however. As part of our master plan, an additional four VLMs are slated for installation, which combined will accommodate 80% of the inventory in the main parts warehouse. This will transfer a total of 32,000 ft² [2972.9 m²] from the main warehouse to the manufacturing floor."

The tool crib’s 2000 ft² (185.8-m²) area has now been reduced to a total of 300 ft² (27.87 m²) by using the VLM. The electronics center warehouse has also reduced from 800 ft² (74.32-m²) to 72 ft² (6.69 m²). Combined, all three areas have provided more than 34,000 ft² (3158.7 m²) to manufacturing.

"The main warehouse VLMs have reduced staffing by two workers, down to 15 staff, a 15% reduction in labor-hours," Hockaday explains. "Two operators work the four shuttles. The tool crib has reduced its staffing by one worker, a 50% reduction in labor-hours. The electronics center continues to be self-serving. In total, the VLMs have enabled the reduction of more than 100 labor-hours per month from warehousing staff, which have been reassigned to other needed areas of the plant."

The warehouse has consistently maintained a fulfillment accuracy of approximately 98.0% prior to the use of the VLMs. After VLM installation, however, the order fulfillment accuracy rate jumped to 99.5%. ME

 

For more information on Remstar, go to www.remstar.com, or phone 207-854-1610.

 

 

Vision for Good Medical
Manufacturing Quality Inspection

ATL, formerly known as Ad Tape & Label Co. (Menomonee Falls, WI) was established in 1951 as a small, family-owned printer. Manufacturing its products from table-top presses, the company was named after its original product line of advertising tape. In 1963, ATL incorporated as Ad Tape & Label Co. Inc. focusing on the production of labels for the industrial and direct-mail markets.

Following the sale of the company to an employee in 1987, ATL continued to expand its markets and product lines, specializing in producing customized labels for the industries’ largest printers and direct-mail companies. Twenty years ago, ATL formed a second division where the business focus shifted to servicing the medical industry by converting forms and tapes into disposable medical devices.

In 2003, ATL earned its FDA cGMP (Current Good Manufacturing Practice) acceptance as a result of strict compliance to 21 CFR (Code of Federal Regulations) Part 820, for the manufacture, packaging, and storage of disposable medical devices. In 2007, ATL became a "private brand" manufacturer of medical devices and began direct shipment from its Wisconsin plant to stores/distribution centers worldwide. ATL also follows cGMP 21 CFR Parts 210 and 211 for manufacturing, processing, and packaging (for all pharmaceutical label manufacturing).

In 2007, ATL Security Label Systems was established to provide an new advanced line of labels, offering security and anti-counterfeiting features, including invisible digital forensic marking, track and trace, mass serialization, custom codes, 2-D barcodes, color shifting authentication, covert machine-readable markers, and antimicrobial labels and packaging.

ATL’s products undergo rigorous quality checks at each stage of design and production. To help maintain its commitment and reputation for excellence, ATL makes regular investments in state-of-the-art inspection equipment. The most recent acquisition was a Kestrel 200 optical measuring microscope from Vision Engineering (New Milford, CT).

"Although we were previously able to adequately measure die cuts and spacing, along with the location of prints with our existing technology, we felt that this was an area for potential upgrading," explains Greg Gilanyi, ATL quality manager.

"Having researched the alternative optical measuring microscopes, including demonstrations of the most applicable units, we chose the Kestrel 200. Our new Vision Engineering microscope delivers fast and accurate two-axis measurements, aiding our precision and speed of operation. The sharp, high-contrast images provided by the Kestrel’s advanced optics enable our staff to examine work in greater detail. The superior optical image of the unit even allows difficult-to-view features to be measured on low contrast items, such as black or transparent labels," says Gilanyi.

ATL President Donald Dobert explains the need for the investment: "We were looking for a unit that would allow us to expand our FDA cGMP compliance. The Kestrel allows us to measure critical die cuts down to 0.0001" [0.003 mm]. We constantly perform IQ-OQ-PQ [Installation/Operational/Performance Qualifications] in our Systems Validation Protocol, and the Kestrel unit provides us with accurate and precise measurement. From this, we can determine process Cpk and quantify to our customers our quality in terms of defects per million."

Dobert continues: "We perform instrument repeatability and reproducibility studies so we can prove that measurement error doesn’t induce false readings into our validations or Cpk capability data. I can tell you from my background of more than 30 years in quality, that the Kestrel unit is one of the best devices I’ve ever used."

With data processing performed by a QC-200 multifunction microprocessor, the Kestrel 200 was designed to be simple and easy to use for offline quality control routines performed by the production staff. The Kestrel 200 is the smallest member of Vision Engineering’s optical measurement range, and is well-suited for measuring 2-D features of small, intricate parts with a high-precision measuring stage of 6 × 4" (152.4 × 101.6 mm).

The Kestrel 200 uses Vision Engineering’s Dynascope technology to provide enhanced surface definition for fast and simple measurement and optical clarity that allows detailed visual inspection to be performed simultaneously. Unlike video systems that digitize captured optical information, the Kestrel 200 employs a pure optical image. There is no image processing before the measurement, allowing component parts to be measured with confidence. ME

 

For more information on Vision Engineering, go to www.visioneng.us, or phone 860-355-3776.

 

This article was first published in the August 2011 edition of Manufacturing Engineering magazine.  Click here for PDF

 

 

 


Published Date : 8/1/2011

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