Lean and business management consultant at Mountain Ridge Consulting, https://www.linkedin.com/in/edwardgemin
The ideal changeover should be tool-less. This means standard bolts used in changeovers are the enemy and must be identified and replaced. We need to look at the bolts and how they are used and determine if there is a better fastener. Bolts are commonly installed as a cost-effective measure to secure items together. This is from the machine/equipment designer perspective, who usually looks at the cheapest and easiest way for them to manufacture the machine without consideration of the end user or production perspective.
Consider the effort it takes to remove or loosen a bolt. You have to find the tool and retrieve a tool that fits the correct size of the bolt and then you have to apply force to loosen and twist the bolt off. These actions are all waste! In addition to these waste, bolts and washers can get lost, mixed up, can be too long, which all add to the time of the changeover.
When looking at improving changeover time the first thing we do is sort and organize the tools that are needed to changeover the equipment. Once the tools have been sorted, the next step is to set them at the point of use. These steps are just the start, as the actual goal is to remove all tools. There are many devices available to eliminate tools and can be selected to fit best to the application and forces that are applied. It is important to note that before any bolt is removed an engineer should analyze the forces being applied to the current fastener to ensure that you don’t adversely add a safety or quality issue. The majority of bolts can be replaced with cam lever or other tool-less bolts which allow the operator to quickly loosen or remove objects without much effort. Think about your bicycle and how easy it is to adjust the seat post or remove the wheels when a cam lever clamp is used instead of bolts.
When tool-less bolts are not a good fit try powered clamps. Powered clamps can act as bolts that can be turned on and off with a flip of a switch. There are many different types of powered clamping and hold down systems that can be used to remove/replace bolts. For example: pneumatic actuation clamping, hydraulic actuation clamping, vacuum clamping, and magnetic clamping
If for some reason we can’t remove the bolt and we have to live with this necessary evil, we must do everything in our power to reduce the number of tools and turning movements. This can be done by standardizing the bolts to one size and using different type of bolts such as quarter turn bolts, interrupted screws, or course threads verse fine threads. One of the easiest and often overlooked improvement is standardizing the bolt wrench size which is a quick way to eliminate a few tools. I have found that quarter-turn bolts or lock fasteners are great to eliminate a need for a tool all together. These turn lock or quick-action fasteners are often used to secure skin panels on aircraft and other high-performance vehicles and were applied to gain quick access to these compartments. Interrupted screws or breech bolts were used very successfully to reduce the time it takes to change cartages in large cannons.
When you are working to streamline the internal and external tasks of the changeover, look at how fixtures are mounted and how adjustments are made. Most of the time you will see bolts applied to these situations, which can be replaced. Consider the different solutions and waste mentioned above when analyzing and breaking down your changeover tasks. These small changes just might have a big impact on your changeover and downtime of your equipment.
