In fact SMED equates to changeover in less than 10 minutes!
Having already tried videoing changeovers and studying them with a team, this seemed like quite a tall order. However I was soon to discover there was far more to reducing the time than just looking for waste on a video.
In the last blog we looked at the benefits gained by improving your set up times.
In this blog we look at a structured technique and 5 tips that will enable you to halve the time your machine is stopped. These work whether it is an old press or the latest 3D printer.
The four step technique
Step 1: Capture the current situation.
Use a video to capture the whole changeover. Break it down into work elements and record them on a Standardised Work Combination Table.
Changeover time is defined as the amount of time taken to change a process over from the last part of a production run to the first good, repeatable part of the next production run.
The phrase “first good repeatable part” is important. It’s not unusual to find processes where the first part may be correct but subsequent parts are not. Or extrusion processes where changes in material or colour take a while to be purged.
Step 2: Separate internals from externals. Decide if each element is an internal or an external using these descriptions.
Internal Element – any work element that cannot be carried out safely unless the machine is stopped, e.g. tool changes, material alignment
External Element – any work element which can be carried out safely while the machine is running, e.g. preparation of tools, materials etc.
Now re-organise the steps. Put all the external steps either before or after the machine is stopped. Look how the red stop time decreases.
Step 3: Convert the internals to externals. This usually involves some physical change to the equipment allowing you to move yet more elements to externals.
Step 4: Eliminate the waste. Use the 7 Waste technique and the tips below, to further reduce the length of the red bar.
5 Top Waste Elimination Tips
1. Reduce the need to measure and make adjustments. Aim to pick and place tooling into the exact location, first time. Use:
- Block gauges.
- 1 fixed datum point.
- Colour coded location lines, or match marking, for different tools.
- And configure and label setting gauges.
2. Simplify and standardise the tools used.
By standardising the tooling dimensions, we could use tools that fit instantly instead of having to use adjustable tools.
3. Bolts should be treated as the enemy!
- Rigorously eliminate them. In this example we used 1 quick release catch instead of 2 screw fastenings.
- Make sure any remaining bolt heads are a uniform size. This reduces the time it takes you to search for and pick up different hand tools.
- If Allen keys are used, weld them into position. This saves you handling time.
- If bolts are the only option, ensure that the bolt length is reduced to the working minimum.
4. Avoid using cranes and hoists. They are slow.
- Use tables or scissor lifts set at the access point height. Prepare as an external.
5. Always keep a good 5S standard. External preparation, configured tooling and clean equipment all save time during the set up.
Remember every second counts! If you would like more examples or any assistance on SMED please contact the team.