Last month's article examined eliminating transporting and trouble during setup. This month's article continues with eliminating tape measures and dial indicators and making the setup one-touch.
Step 12 - Eliminating the Tape Measuring and Dial Indicating During Setup
When working with companies to reduce setup time, it has been found that the use of tape measures, scales and dial indicators during setup is common. Many times, tape measures and scales are used to verify the length of cutting tools from the holder as well as verifying the positioning of the fixtures. Dial indicators are used to position fixtures, indexing heads and other items during setup.
The use of tape measures, scales and dial indicators is not efficient in setup and leads to poor start-ups. The measuring tool combined with the operator's method of use, sight and mental calculation leads to many opportunities for error. It is recommended that you discontinue their use for setup.
Just think how many times you have taken a measurement and then cut the board to the wrong length. People who use tape measures for a living follow the rule "measure twice, cut once." Still, we expect employees to use those same tools and get exact positioning during setup. Tape measures, scales and dial indicators are used inconsistently, read improperly and time-consuming.
A better method would be to use hard stops, locating devices, positioning pins or other such positioning devices. For example, if cutting tools cannot be pre-set when CNC machining, one option is to identify a location on the fixture or make a known block placed on the table of the machine tool and touch off the cutting tool. This would be faster and more exact than measuring. Another solution may be to install dowel pins and bring your fixtures and indexing heads up to that known position to eliminate dial indicating.
Proper labeling of change parts also will eliminate the need to measure those parts every time they are used. If you have many change parts that vary slightly in size (inside diameter, outside diameter, length, etc.) you should permanently label those parts so they never have to be verified again with any measuring device.
Far too often, operators are measuring raw materials during setup. This is a waste of time, especially when you realize that someone prior to the setup had to determine if this material was acceptable to be issued for the job. This occurs after your receiving inspector checked the material when it came into your facility.
A good practice to incorporate is that the first time material is verified for any dimension, it should be identified with that dimension to eliminate the need for future measuring. In working with your suppliers, you may be able to have them identify the material before it gets to your facility. If you consider all of the time spent measuring in your plant, it's certain that you will want to eliminate as much measurement as possible - especially while your machines are stopped for setup.
Step 13 - Making Your Setup One-Touch
When you consider making your setup reliable, rapid and repeatable, the goal is making it one-touch, which means that with one motion, part of the setup change is made. For example, use one-touch instead of loosening, moving, tightening and re-adjusting during start-up. While this may seem impossible to you today, it may be easier than you think. If you have known positions and repeatable settings, you may be able to achieve one-touch sooner than you think.
Standardize Clamping Height and Position
For most of you, your production quantities are one or a very small lot size. Still, you could standardize clamping heights and clamping locations by mounting your fixtures on sub-plates. This applies to modular fixturing as well.
Alternate Methods of Clamping
There are numerous ways to clamp without bolts and nuts. Pneumatic clamps, hydraulic clamps, vacuum clamping and magnetic clamping are just a few. Your goal should be to develop clamping methods that require one touch to position the clamp and activate the clamping power - such as a pneumatic valve lever for pneumatic and hydraulic clamping or electrical power supplied to activate magnetic clamping. Most of these methods can be disconnected from the air or electrical source with fail-safe clamping.
Most machine tools, fixtures and gauges are made to be infinitely adjustable by the manufacturer, which causes your setups to be longer than desired. In your examination of current setups, you may find there are many ways to make your machines, fixtures and gauges one-touch setup - fixed positions, hard stops and location pins are all possibilities for improvements.
One system of locking a base plate onto a machine involves the use of mushroom location pins and a locking device that resists stress forces in the X, Y and Z axes. It is mistake-proof and only needs one touch to install.
One way to determine if your one-touch improvements are suc-cessful is by conducting a start-up audit. This audit should include baseline settings and positions, which are verified during start-up. You will find that many of the steps completed during the changeover can be improved through one-touch.
There are many excuses for not making the one-touch improvement and below are just a few of the common ones. But be cautious because not making this move may stifle your company.
- "We don't need to make it one-touch because it's only taking off a few seconds."
- "It doesn't take that long with the existing method of setup."
- "I have to wait anyway, so why make this part of the setup faster?"
- "That improvement won't work at this plant."
- "It costs too much to implement one-touch."
- "Management won't support it."
- "Why spend the money to reduce this part of the setup?"
Many one-touch improvements implemented today are a result of brainstorming sessions during which some participants said it couldn't be done. It is worth the time and effort to make as much of your setup one-touch as possible.
Once you develop one-touch improvements to your setups you need to make the necessary changes to your setup procedures and documentation. Never assume everyone understands the improvement and certainly don't expect employees to do the setup correctly without training.