Cambio rápido de herramientas en serie con productos de gestión visual
SMED - Fast serial tool changeover: Single Minute Exchange of Die
THE SMED GOAL:
This is a method of working that sets out to reduce changeover time on production runs. The main people involved in the process are asked to participate in an exercise whereby tooling must be set up according to a precise specification.
One goal: “total productivity”
Better organization first, then more simplicity.
Motivation first, then ongoing motivation.
- - The participants discover opportunities for improvement and learn the virtues of analysing how a process is organized.
- The payback is plain to see and visible right from the first project, with no substantial outlay.
- The use of the machine resource is optimized, with
* increased capacity (therefore lower unit cost)
* more flexibility in responding to customers' needs
* the effectiveness of visible, motivating actions
The objective is to reduce changeover time on production runs to a quantifiable objective.
4 steps are needed to achieve this:
- - Eliminate operations that serve no real purpose; convert stopped machines to running machines (forward preparation of ancillary gear). - Simplify flanges and fastenings (e.g., quick-fit couplings). - Put several people on the job (like a formula 1 pit stop). - Simplify adjustments and trial runs and reduce the number of tasks while the machine is stopped (e.g., settings sheets).
Some common obstacles are encountered when implementing the SMED method in practise:
- - The belief that rapid changeover is best solved technically When the company system starts seeing excessive production changeover times, the problem is most often posed to the technical staff, who is asked to implement a machine-specific technology for reducing the time.
- - “Electric trains”
Faced with a market demand that at the time was higher than supply, makers and designers brought out machines capable of ultra-high throughput rates but neglected ancillary times, including setting up.
One such example is “electric trains” which are very high performance machines as regards throughput but are highly complex, similarly to certain transfer machines.
- - The idea that job changeovers are not repeatable operations
Changes of production on the same machine are not always tackled the same way. Yet changeover operations can be analysed exactly as can production operations, with a written procedure produced.
- - Badly defined objectives
The objectives of the “method” services are usually set in terms of productivity gains. What would be more interesting is to define those objectives in terms of “total productivity”, taking account not only of the instantaneous throughput but also the notions of materials handling, production changeovers, production time cycle, etc.
- - Too much specialization
Current ways of thinking have completely changed the way manning is organized. These days production departments favour versatility in their staff.
All these issues suggest that a SMED project cannot be implemented except in a framework of high motivation among the staff.
The corporate project, clearly indicating the axes along which work will be directed, must be common knowledge among the whole of the workforce. Numerous company functions are involved: planning, purchasing, tooling, production engineering, design, sales, stores, etc.