Custom Bending Company Cuts Lead Time and Boosts Productivity
by Don Kivell
Reduce costs. Cut lead times. Improve quality. These are challenges manufacturers face every day; not just to enhance the bottom line, but to survive. Speed and responsiveness might well be the currency of the future, and to have it means proper positioning now. That's the thought of Don Hockin, president of UltraFit Manufacturing Inc., a Mississauga, Ontario-based tube and pipe bending and fabricating company.
Not long ago, UltraFit was a typical batch manufacturing company - machinery required to complete the process was located in different areas of the plant; tube bending in the bending department, tube-end sizing in the end finishing department and welding of brackets and flanges to tubes in the welding department.
Long changeover times on tube bending equipment meant the manufacturing department produced parts in groups. Sometimes orders were batched together for two-week periods or longer, to be run during the same set-up. Because the process was time consuming, there was a tendency to produce as many parts as possible to maximize run time of the equipment, and amortize costs over a larger production volume. The practice created a need for higher levels of finished goods inventory to create a safety stock of parts and prevent shortages at shipping. In turn, this increased inventory required more floor space for both finished goods and work in process. Finally, with larger production runs, less variety of parts could be made each day, thereby inhibiting UltraFit's ability to meet short lead-time requests from their customers.
New lean goals
The management team established goals to reduce inventory and improve the company's ability to produce in smaller batches. The team felt that meeting these objectives would free up floor space to add new equipment and processes, create improved cash flow for the investments required and improve response time to customer order requests.Initially, UltraFit set out to effect improvements internally; however, managing the change generated limited success, and it wasn't happening as quickly as the team hoped. Management decided an outside pair of eyes might help to expedite improvements and they called in Hamilton, Ontario-based consulting firm Lean Manufacturing Solutions Inc.
Their objectives? Reduce distances traveled, non value-adding activities, manufacturing lead times, in-process and finished goods inventories and implement one-piece flow and quick changeover on the tube bending equipment.
To simplify the project, a single machine and single department became the focus. "Our machine number 307, an Addison 76 bender, is a versatile workhorse for us because it has the ability to bend many different diameters of tube from 1.50 inches to 3.00 inches," says Oscar Pizzani, plant manager for UltraFit Manufacturing. "Given the time-consuming changeovers that were part of the problem, it was the right place to start."
Shop floor employees and support personnel from the scheduling, supervision, engineering and maintenance departments came together to look at processes and break them into components. The team measured and mapped the manufacturing processes and used a video camera to record an actual product changeover on the bender.
Results of the mapping exercise, and the analysis that followed, revealed that at any given time there were two-hundred pieces in process. Changeovers took between 40 minutes and two hours. Parts were required to travel 150 feet, and lead-time consumed as much as two weeks. It took that long to complete the manufacturing process from start to finish. This included time spent waiting in queue between stages while subsequent operations were finishing off other orders.
The next step was to create a desired future state process, then set out to make it happen.
Lesson learned
Initially, a manufacturing cell was created to comprise bending, end finishing and welding. By eliminating the work-in-process inventory created by large batch flows, the team was able to fit the new cellular production layout into the same area, and use less floor space. The production line was balanced and moved to a one-piece flow where downstream operations pulled production through the cell, rather than allowing faster operations to work ahead and create inventory traffic jams. Communication improved and the work team cross-trained each other to facilitate job sharing and rotation throughout the day.A review of the set-up video also revealed other improvement opportunities. Screws and bolts were eliminated and replaced with quick-locking toggle clamps. Tooling spacers were added to existing dies to eliminate the need for adjustments on the machine. This reduced total set-up time and had the ancillary benefit of reducing variation between set-ups.
The process is now faster and more consistent, yielding higher machine utilization and a reduction in scrap. Reduced set-up time also enhances manufacturing flexibility and allows a greater number of different parts to be produced each day. This reduces the need for 'safety stock' inventory and improves responsiveness to customers' needs.
The net result
Overall, set-up times were reduced by 90 percent and work in process was almost eliminated. In fact, the end finisher whose work cycle was quicker than the welder, now loads the welding fixture while the welder removes the completed part, attaches an identification label and places the piece in the finished rack where it is ready for shipment.
