Production Tips, part one
by Nicholas C. Weidhaas
"Production Tips" courtesy of Woodworking International
(Editor's note: This is part one of a three-part series.)
Evaluate your potential "cost savers".
Focus on the handling of parts at the machine.
- Extract the finished part from the machine.
Locate small work tables or platforms at the machine.
Keep the machines operating by doing the handling while the machine is running.
Utilize multiple loading stations, such as the type found on many shapers. While the machining operation takes place at one work station, another can be used for loading or unloading.
Preposition the stock as close as possible to the loading point considering all safety factors and in correct orientation to speed loading and minimize the unproductive time of the machine. This can take some preplanning, such as orienting the finished part on the truck at one operation in such a way as to minimize loading time at the next operation. How many times have you seen an operation where the operator first had to turn the part over or end-for-end before it could be worked on Ė while the machine stood idle?
Eliminate as much of the handling as possible.
For non-critical parts, eliminate handling by tossing the part into a box rather than carrying it to and carefully placing the part on a finished parts truck. Automatically discharge the part from the machine into a box.
Use scissors lifts to avoid the very time consuming "bend and arise" which are necessary when the operator must secure stock to work on from near the bottom up a stack of material.
Install movable "end" and "back panel" devices which can be either attached to the factory trucks or be moved in next to the materials handling conveyors as needed. These panels provide a "stop" or "wall" which the parts can be piled against. This makes the loading of the trucks much easier (and faster), particularly for small parts which tend to fall off of the truck, since much of the careful positioning which would need to take place in the absence of the "walls", is eliminated.
Install quick-acting clamping devices if clamping devices are necessary to hold the stock during machining. Avoid clamps entirely, and time consuming "careful positions" when safety is not jeopardized and other factors permit.
While the part is at the machine perform as many operations on it as possible.
Focus on "balance" problems.
The boring machine is set on automatic cycle, and the operator is much faster in his handling operation than is the cycle of the machine. How can the machine cycle and the operators handling cycle be made to more closely coincide or "balance"? Could the machine cycle be increased? What additional work could the operator perform rather than to "wait for the machine" and lose valuable productive time. An excessively long machine "stroke" often contributes to this type of imbalance.
One operator frequently waits for the other operator in a team operation. Often "job assignments" need to be redistributed to reduce this type of imbalance. Sometimes, team operations should be broken up, and each operator should work independently.
Conduct a work sampling study
Hereís how itís done: the supervisor (or engineer) simply walks through his or her department with a pad and pencil, looking mostly at the floor, or away from the workers whose activities he is going to analyze. Then suddenly he looks up at one of the workers and observes what the worker is doing at the instant of observation. Usually the supervisor simply checks off which of the pre-established categories of activity the workers activity falls into at the first instant of observation.
Typical categories are: working, idle, missing from job, and trucking materials. Observations can be further broken down to include the reasons for the idleness such as waiting for machine to complete cycle, or waiting for another team member to complete his assignment.
At first it is usually best not to get too complicated, and have too many categories of activity. The analyst observes first one worker, and then another and another. . . As he casually walks through the department, noting category of each workers activity.
After about twenty trips through the department, which should be made at random times over a one to three day period, the analyst can summarize the observations for each of the operators. His results will show something like this (but with more workers):
The analyst then evaluates the data and asks such questions as:
- Does 62.5% overall working time suggest a reasonable level of efficiency?
The technique is simple, but very powerful and revealing. Try it in your operation!
Find your bottleneck or limiting operations.
For more infomation, including videos, books, and training programs, visit the: The International Productivity Center Web site at http://www.woodvideo.com/. Their products are designed to assist manufacturers of lumber, furniture, cabinets and similar wood products in their machine operator and supervisory training efforts.