A custom metal fabrication shop/vehicle assembly facility had an arduous process for each unique vehicle they produced. Engineering would send the drawings down to the metal fabrication shop for the unique cut pieces from plate (including diamond pattern), and the structural angles for construction of the vehicle frames. The metal fabrication shop used a cut optimizer program to get the most shapes out of each stock plate used.
The cut pieces were then marked by chalk with the corresponding number from the drawings that the operator needed to discern from the drawings. Often there would be similar appearing pieces, maybe one for the right side of the finished assembly and one for the left that would be mismarked by chalk, resulting in problems upstream in the forming process or during assembly and welding. This resulted in making additional cuts from plate in the metal shop, thus slowing down the assembly process, wasting extra material and production time, while losing the material optimization from the use of additional raw plate stock.
Remaining usable plate stock was often set aside in hopes of being used for other cuts, but the optimization program was only capable of being used for new, whole plate stock, so large stacks of off-cuts were left unused within the shop. The off-cuts were often left unmarked, so the potential of using them in the future was minuscule, due to not being able to positively identify the metal’s properties for future jobs. Hence, much waste metal resulted within this plant. An average of 500 pounds of metal scrap was generated for each vehicle produced, not including the additional usable off-cuts that piled up unused and unmarked.
Although this shop’s operations may be similar to many other manufacturing operations, their product was unique in almost every case. Many opportunities for improvement existed beginning with: The receipt of raw materials and subsequent transfer of raw materials to work in process, tracking jobs at major fabrication points, managing raw material components and component shortages, capturing serial numbers and process comments, cutting and staging components and subassemblies, and managing Q. A. and final inspections. They included:
Reduce manufacturing costs by eliminating non value added labor Reduce direct manufacturing costs Reduce indirect and overhead costs Significantly cut material waste Improve work flow management Streamline QA and inspection processes Optimize and track off-cuts for future use Increase production capacity Improve inventory control Improve asset utilization Improve customer service Improve profit without increasing revenue
A key element in the cutting process was that of the optimization of plate stock. ADI developed a program to work in unison with the plate optimization program wherein a bar coded label identifier was generated for each cut from the plate, including a schematic for the location and shapes on which each label should be placed, along with any remaining usable off-cut(s). Using the schematic generated from our solution, the operator labeled each cut. The labels were then scanned before use upstream to assure that the correct pieces were being used for forming and fabricating.
The off-cuts were also prioritized through the program for use in subsequent jobs, where that material would be the first choice for cuts that would fit within the dimensions of the material size of the off-cut. Hence the waste from unused off-cuts diminished considerably. Waste from using the wrong pieces up stream in fabrication and assembly reduced to a very low amount and were no longer generated from misidentification.
Likewise, metal angles at the cut saw were bar code labeled and tracked to make certain that each piece was subsequently used in the correct way during upstream fabrication. Significant savings were again realized, not only from reduced scrap, but more so from:
1. Automating the process of preparing raw data from the existing system and presenting that data to the panel optimization software. Replacing inefficient methods with a robust optimizer that included: a. The ability to be imbedded into other application software or the ability to be utilized in an automated fashion. b. The ability to keep track of, manage and utilize off-cuts. c. The ability to produce output compatible with downstream system requirements for displaying cut sheets, producing labels and allowing machine operators to prioritize cutting and label printing. 3. Creating a SQL database schema that would provide a foundation for the management of the cutting data and for part and raw material IDs to be associated to job IDs. This database would become the transaction repository for all data collection efforts going forward. 4. Data links to item and job data as appropriate 5. Creating user interfaces to interact with the developed application for administrative and functional interactions. 6. Creating labels and user interfaces that allow the machine operators to select and prioritize which cut sheets they are working on and in what order and by what method labels are printed.
Implementation of this system resulted in: 1. Elimination of direct labor previously used to prepare data cutting. 2. Elimination of errors that cause downstream cutting problems linked to manual data preparation. 3. Elimination of the lag time between the time raw job data is available and finished cut sheet and labels are ready. 4. Elimination of labor required to print and distribute cut sheets and labels 5. Elimination of rework required to replace misplaced cut sheets and labels 6. Elimination of wasted labels (only labels required will be printed, no wasted blanks) 7. Easier to read labels that include a bar code to facilitate subsequent data collection processes 8. Better visibility and management of sheet and tube inventories, including off-cuts. 9. Reduction of scrap by way of more complete use of raw materials (tracking and use of off-cuts)
The results were impressive, delivering significant additional profitability to the ADI customer. An additional benefit was that the productivity of this facility significantly rose due to these added efficiencies, allowing them to sell more vehicles through the year and raising greater revenue. The lead time for vehicles also improved delivering even greater satisfaction for their customers.
- Written by John McBride, ADI employee