Information & Training. | Lean Manufacturing. Just In Time Processing.
Information & Training. | Lean Manufacturing. JIT Processes.The standard manufacturing process demands that process and test equipment is routinely taken “off-line” in order to permit product mix changes, to perform routine maintenance checks and repairs, to allow verification and validation activities, to support engineering test runs, etc.. The effect of such activities can be to significantly impact overall process efficiency. The time that an item of process equipment is not fully utilized in outputting customer required product is wasted time, which needs to be made up by the installation of excess production capacity, provision of extra labour hours, etc..
The objective of a setup reduction effort, is to minimize the time which process equipment remains “off-line” and unavailable for productive purposes.
Setup reduction and the lean process.Set-up reduction becomes critically important when an organization seeks to implement a lean method of operation. Lean is focused on continually reducing lot/batch sizes in order to build greater flexibility and responsiveness into the process. Clearly a highly flexible, responsive process will have the advantage of being able to rapidly adapt to changes in customer demands, however, process flexibility demands frequent product mix changes and continuous product revisions. Consequently, process and test equipment will need to undergo frequent changes. Only where changeover and set-up times are short can an organization successfully implement lean and obtain the cost, quality and competitiveness benefits.
SMED – Single Minute Exchange of Die. OTED. OTC.Dr. Shigeo Shingo developed the SMED concept, where the objective was to complete machine changeover and set-up reduction in less than 10 minutes. The concept was detailed in his book “A revolution in manufacturing. The SMED system”.
The concept was further expanded with the OTED (One Touch Exchange of Die), OTC (One Touch Changeover), where a target of less than one minute became the objective for set-up & changeover times.
Setup reduction is driven by the need to be able to changeover a given process to produce a different product in the most efficient manner.
Reducing setup (or changeover) is a lean manufacturing technique allowing the mixing of production/products without slowing output or creating higher costs associated with non-value adding activity.
Changeovers add no value and therefore should be minimized. The goal is to reduce and/or eliminate downtime due to set-ups and changeovers.
The set-up process should be viewed from two different perspectives, one is “internal”, the steps required to be completed when an item of equipment is stopped versus “external” steps accomplished off-line while the machine is in operation.
Quick changeover will increase productivity, reduce lead-time, lower total costs, and increase flexibility to adapt to a changing market and/or product mix.
As setup and changeover times decrease, then lot/batch sizes can be reduced, in turn creating a more flexible process with consequent cost, lead-time benefits.
SMED technique.As outlined above, Dr. Shingo proposed that a process changeover should be viewed in two ways, specifically as the “internal set-up” and the “external set-up” activities. During the “internal set-up”, the item of equipment must be shut-down in order for the change-over activities to be performed. During the “external set-up”, the item of process equipment can continue to operate as normal producing good customer required outputs.
In every process set-up and changeover, the necessary activities will be performed before, during and after an item of process equipment is shutdown.
There are four stages in the SMED approach:1st stage: Identify the complete range of activities which need to be performed in order to complete a set-up and changeover.
2nd stage: Having identified all the activities, now determine which can be performed “off-line”, i.e. while the equipment continues to operate as normal and those activities which impact equipment operation, i.e. “internal activities”.
3rd stage: Each of the “internal” activities now need to be examined, to see can they be sub-divided, reduced in scope, reformatted in order to either transform them into “external activities” or at least reduce the “internal activity” effect.
4th stage: Continue to examine all activities, both “external” and “internal” with an objective of minimizing the total set-up and changeover time.
Implementing a “setup reduction” effort.There are an infinite number of approaches to optimizing equipment set-up, however widely applied implementation can be along the following lines:
Understanding the current status:
– Visual understanding of the current situation.
– Flowchart the current process.
– Document into an SOP (Standard Operating Procedure).
– Record resource demands, including times.Completing the above tasks, forces a comprehensive understanding of how a set-up is performed. In many set-ups, there can be a level of tweaking, e.g. only a particular operator knows how to perform, etc.. Unless the current situation is clearly understood, defined and documented, then it is not possible to progress.
The “internal” versus the “external” tasks.
Create a list of all the tasks.
Spilt the list into two. Any task which impacts of the routine on-going performance of the item of process equipment, needs to go into the “internal” list.
All other tasks are “external”.
The “internal” tasks now need to be examined. This is the start of changing the actual process performance, therefore, will require input from equipment operators, maintenance technicians, engineering, quality personnel, etc..
Essentially, a quality improvement team will need to be actively involved in re-shaping the set-up and changeover process.
Examine each of the “internal” tasks.
Identify those where there is an opportunity to re-shape the task, to either reduce or eliminate the impact on the operation of the process equipment.
Propose a change to the process SOP and the associated process flowchart. The change should go through a formal change control process, to ensure all relevant stakeholders review and approve the proposed change.
Where approval is received to implement the changes, proceed to implement.
Monitor and publish the results. Confirm that there is a positive impact on the shutdown times of the equipment.
The improvement team will now proceed to review the “external” tasks. As per the “internal” tasks, each activity associated with the set-up process will be examined. Changes will be proposed, this may utilize improvement tools such as brainstorming, cause and effect, etc.., approvals sought and where received the changes will be implemented. This process needs to continue until the set-up and changeover times are reduced to levels deemed optimum by the organization.
Information & Training.
Lean Manufacturing & Just-In-Time Processes.
The tools and techniques of Lean & JIT:
– Basic working practices
– Total Productive Maintenance
– Design for manufacture
– Set-up reduction
– Operations focus
– Total staff involvement
– Overall Equipment Effectiveness (OEE)
– Visual management
– Flow layout
– Just-In-Time Supply
– Pull scheduling & Push systems of control
– Kanban control
– 5S method of control
– Levelled scheduling
– Etc. Etc..