Quick Changeover – SMED
SMED is the term used to represent the Single Minute Exchange of Die or setup time that can be counted in a single digit of minutes. SMED is often used interchangeably with “quick changeover”. SMED and quick changeover are the practice of reducing the time it takes to change a line or machine from running one product to the next.
The successful implementation of SMED and quick changeover is the key to a competitive advantage for any manufacturer that produces, prepares, processes or packages a variety of products on a single machine, line or cell. SMED and quick changeover allows manufacturers to keep less inventory while supporting customer demand for products with even slight variations. SMED has a lot of hidden benefits that range from reducing WIP to faster ROI of capital equipment through better utilization.
To understand how SMED can help we have to look at the changeover process. Typically when the last product of a run has been made the equipment is shut down and locked out, the line is cleaned, tooling is removed or adjusted, new tooling may be installed to accommodate the next scheduled product. Adjustments are made, critical values are met (die temperature, accumulators filled, hoppers loaded, etc.) and eventually the startup process begins ñ running product while performing adjustments and bringing the quality and speed up to standard. This process takes time, time that can be reduced through SMED.
Effective SMED programs identify and separate the changeover process into key operations ñ External Setup involves operations that can be done while the machine is running and before the changeover process begins, Internal Setup are those that must take place when the equipment is stopped. Aside from that, there may also be non-essential operations. The following is a brief example of how to attack the SMED process:
- Eliminate non-essential operations ñ Adjust only one side of guard rails instead of both, replace only necessary parts and make all others as universal as possible.
- Perform External Set-up ñ Gather parts and tools, pre-heat dies, have the correct new product material at the line ñ there’s nothing worse than completing a changeover only to find that a key product component is missing.
- Simplify Internal Set-up ñ Use pins, cams, and jigs to reduce adjustments, replace nuts and bolts with hand knobs, levers and toggle clamps ñ remember that no matter how long the screw or bolt only the last turn tightens it.
- Measure, measure, measure ñ The only way to know if changeover time and startup waste is reduced is to measure it.
Always measure time lost to changeover and any waste created in the startup process so that you can benchmark improvement programs.