The key to doing Setup Reduction (Changeover Time, Turn Around Time, or Make Ready Time Reduction depending on the industry) is truly understanding the following three terms and their definitions:
External Element of the Setup
Internal Element of the Setup
Setup Time - The elapsed downtime between the last production piece of part "A" and the first good production piece of part "B". In Healthcare, for room turn around time, this would be patient "A" and patient "B".
Note that the first good production piece of "B" is included in this setup time. This is to account for a potential series of adjustments that may have to be made in the setup for "B", in which case the first piece may not be a good piece.
One of the goals of setup reduction is to eliminate adjustments.
External Element of the Setup - That part of the setup which can be done while the machine is still running. Some examples are: bringing the raw material, drawings/work order packet, tooling, or fixtures to the machine while the machine is still producing part "A".
Or in the case of healthcare, this would be bringing all the supplies and linens (perhaps on a cart) required to turn around the room while the "A" patient is still in the room or surgical suite (like the people who clean rooms in a hotel.)
The goal of the external element of the setup is to eliminate the need for the setup person(s) to leave the machine/room for any reason once the machine has produced its last piece of "A." This is primarily accomplished through 5S activities, setup carts, and related documentation.
External setup "waste" occurs when we must look, search, or hunt for any required setup materials even if the machine is still producing "A."
Below are activities which support the external element of a setup goal of never having to leave the machine during the setup.
|Setup Cart |
|Setup Cart Checklist (Usually attached to the setup cart) |
|Comprehensive Equipment (Mold) Setup Preparation Checklist |
This is the easy part of setup reduction - assuring all the "external elements" of the setup are being done externally. Now we can move on to the more difficult part of setup reduction - reducing/eliminating the "internal elements of the setup."
Internal Element of the Setup - That part of the setup which must be done while the machine is shut down. For example, removing or attaching fixtures, dies, tooling, parts, etc. (assuming no pallet exchanger). For healthcare, we must wait until the patient leaves the room.
The ultimate goal is to try to move everything that is currently "internal" to external. For example, for machine tools with pallet exchange and resident tooling and programming, the setup is limited to the pallet exchange and program loading time, which generally can be done in single minutes or even seconds.
While this scenario is very difficult for many setups, it is this type of "outside the box" thinking, ideas, and goal that we must encourage.
The internal element of the setup has the following opportunities for "waste" to reside:
Setup Waste, Internal - Alignment activities required to remove and install tools. For example, the time associated with using a fork truck to maneuver the old tool out and the new tool in while setting up a press. Internal setup waste also includes:
- Unnecessary movement (walking) of the setup person
- The excess effort and time required by the setup people using manual tools in the setup
Replacement Waste - Activities related to removing items from the "A" tool to be installed in the "B" tool. For example, bolts, fasteners, clamps, gauges, and wiring harnesses.
Adjustment Waste - Any activity that would cause the machine to cycle in a sample or trial mode, which could create a part that must be inspected and then possibly scraped or reworked. For example, stroke or stop adjustments.
Internal Element Waste Reduction
Setup Waste, Internal
In general, aligning the tooling is the largest portion of the internal waste. Chain hoists and fork lifts are often used but they pose safety risks and can be brutally slow. Below is a comparison of the most common methods:
Unnecessary motion of the setup person can be studied by using the setup video to develop a process map (also called a spaghetti chart) of the setup person's movements. Analyze the process map to see if adding an additional person to the setup reduces or eliminates unnecessary movement. Two people, working together in parallel, can significantly reduce the movement and time required for this part of the setup. While it is logical to think that adding an extra person to the setup would reduce the setup time by 50%, much larger reductions are possible if there is a large amount of walking/motion required. The figure below shows an example of a spaghetti chart and the parallel operation method. Note that the number of process mapping movements of the setup people should match the steps on the setup process sheet.
Excess internal setup effort and time is eliminated by avoiding the use of hand tools. Power tools should be supplied to all setup people. If special power tools are required for particular setups, they should be included in a setup tool kit or cart.
Replacement waste generally occurs in the acts of removing and replacing fasteners, but it can also mean other waste, such as loading new programs into computer controlled equipment.
While bolts are the most common clamping device, bolts are an enemy of quick changeovers. Remember this for bolts: the first turn loosens, the last turn tightens, and everything in between is waste! Consider the following to eliminate replacement waste:
- Eliminate the use of bolts, nuts, and screws anywhere in the setup
- Use one-motion boltless clamping methods throughout the setup as shown below:
If this is difficult:
- Redesign tooling and the setup so nothing gets removed (bolts, nuts, or anything else) during the changeover. It should only be necessary to loosen fasteners, not remove them.
- Use one-turn clamping devices as shown below.
- Always use power tools.
The goal of this section is to eliminate all tool and equipment adjustments so that the first piece out of tool "B" is a good part. Adjustments extend equipment downtime and cause scrap and/or rework. When documenting a setup, remember that selecting is okay--but adjustment is waste.
Your setup team knows which elements of the setup affect the performance of the tool. Develop a constant numerical value for each of these elements and use that number for every setup.
- Eliminate all visual measurement adjustments requiring the use of scales or calipers
- Use the documented equipment or machine settings
- Use positioning pins and fixed stops
- Use block gauges and templates to select positions
- Use tooling pre-setters
If reference points and center lines are used in the setup, make them visible.