Many people worry that embarking on a lean improvement program will require major disruptive changes and risk. Certainly this can be a path to breakthrough improvements, but it is possible to achieve significant improvements with smaller, incremental, lower risk actions.
During a preliminary walkthrough of a small machining jobshop I observed two opportunities for improvement which could be made at little or no cost or risk. (Once again, walking around and actually seeing proves enlightening.)
What I saw was a large warehouse style shop with lines of milling machines. There was less than one operator per machine. Some machines could run with partial oversight. In general it appeared that both machine capability and the number of machine operators limited how many jobs could be completed in a day. The office was the typical warren of narrow corridors and small cubicles at the front of the building.
Since the jobs were small, irregular, and often unique the office had a very simple system of issuing work orders. A work order document with any required drawings and material specifications was clipped on a clipboard which was laid on a table at the end of the office. I saw at least 20 clipboards on the table. When an operator finished a job he would walk at least 50 yards across the shop then down a narrow corridor to the office area where the clipboards were stacked. He’d turn in the completed clipboard and find the next job in the pile. There was also a coffee pot, bathroom, and a number of attractive young clerks at desks in this area. This arrangement was very convenient for the clerks who had to place the clipboards in a pile, but what was the impact on the operator’s time?
While I didn’t spend enough time in this area to actually measure lost production time I can imagine 20-30 minutes lost between each job. Walk back to the office, wash hands, get a cup of coffee, use the restroom, chat with the ladies, look through the jobs, pick your next job, walk back to the shop, and then start looking for materials, tools, and setting up the machine. During this time both the operator and the machine are not producing billable work.
A quick improvement here would be to create a visual schedule board on the outside of the back wall of the office. The board could be seen from many of the machines operating stations and could create an awareness of how much work needs to get done this shift. The walk to the board would be shorter, the next job would be obvious from the clipboard position on the board, and there are no significant distractions. It might even be practical for the operator to preview and start setting up the next job while a prior job is still running since he would not be out of sight of his machine.
Some further evolutions of this idea would be to place the work orders near the operators/machines or to place the work orders on carts in the shop area. Operators or lower skill assistants could collect the materials, tools, and fixtures on the carts and roll the carts to the machines. Use of job setup carts would create a type of flow in the shop and could significantly increase the operator and machine effectiveness.
A specific part presented another opportunity. In many cases a lean review does not look for waste within an apparent value adding step. Questioning the assumption of value can reveal new levels of improvement. This particular part was a steel piece with a large area which needed to be faced off (machined flat.) The mill was moving back and forth in a zigzag pattern. The cutter moved off the end of the part, stopped, moved over and reversed direction to pass over the part again. Value in this instance is removing metal chips from the part. When the cutter is off the end of the part it is not adding value.
The solution to this is to create a spiral or circular cutting path so that the tool is constantly cutting metal and adding value. This is sometimes called spiral or Z level machining and can be found in trade articles. The interesting point is that this technique can be ‘discovered’ by applying lean waste elimination principles to what most would consider a value adding process.
While Lean manufacturing principles provide many tools and techniques the simplest and most fundamental principle of going out and looking can yield 10% or better improvement with little investment, effort, or disruption.
