Single minute exchange of die

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Single minute exchange of die
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Single Minute Exchange of Die (SMED) - is a tool change within a one-digit number of minutes; method of diagnosing and improving production processes in the processing industry initiated in 1950. by Shingeo Shingo - one of the most prominent contemporary representatives of Japanese science and the practice of organization and management.

The SMED method process

The key issue is the use of methods for improving production processes (e.g. SMED) and production stock management methods (e.g. JIT) is to find the optimum cost of production. Delays in the planned production process often result from machine and equipment failures. In addition, there are delays due to the reproduction of a planning system that does not react to the environment with a planned horizon, which is measured not in hours but rather in weeks. Therefore, the implementation of the universal method of planning and production control - Just In time requires a risk minimization strategy in cooperation with SMED, KANBAN, Total Productive Maintenance (TPM) and TQM.

The process of retooling machines and devices consists of:

  • preparation of disassembly, material verification,
  • disassembly and assembly of tools,
  • centering and setting dimensions and other parameters,
  • making test copies of semi-finished products.

The reduction of the retooling time of the machine increases the time intended for production and at the same time allows to reduce the size of production batches, the quantity of stocks and, as a result, decreases production costs.

The stages of SMED implementation

The implementation of the SMED system is divided into three stages

The first stage is the separation of internal operations from external operations. Thanks to this stage, operations that can be made while machines are being operated are identified, which saves time. With the division of activities, the recording of the film from the course of preparatory operations is checked, which allows you to accurately analyze the activities that are part of the individual operations. Often, checklists are also used, which contain the necessary information about the instruments, tools and employees responsible for the execution of individual operations. These lists are developed for each operation.

In the second stage, try to convert internal operations to external operations. To do this, focus on the preparatory activities that were performed so far with the machines turned off, and find a way to do these activities without stopping production. Such a solution may be, among others, earlier conditions for carrying out the changeover operation. You can prepare it by:

  • preparation of tools and elements that are subject to processing,
  • determine the location of materials,
  • heat the parts to the right temperature.

Reducing the changeover time can also standardize the tool that is used in production, so that you will not need to replace these tools frequently.

The conversion of internal operations into external activities is a difficult stage, it requires searching for new, unusual solutions. The creator of the SMED method presented a set of five questions that can help in this step:

  • What is being done?
  • Who does it?
  • How does it work?
  • Where is it done?
  • When does it?

The third stage of the implementation of the SMED system is the comprehensive improvement of the rearming operation. This stage consists mainly of:

  • improving the process of transport and storage of tools and materials,
  • identifying activities that can be performed in parallel,
  • searching for solutions that facilitate the assembly of individual elements and shorten its duration.

Techniques used in the SMED method

List of questions

  • applies to all parts and operations necessary to replace the tool;
  • includes a list of instrumentation, data on pressure, temperature and other setting parameters, numerical quantities for all measures and dimensions;
  • it is based on double verification to detect faults in the conditions of the operation.

Verification board

  • it complements the list of questions,
  • allows you to verify the completeness of the elements necessary to make the changeover thanks to the parts and tools defined on it,

An attempt to function

  • provides confirmation of the technical condition guaranteeing efficient operation,
  • it postulates, among others, standardization of machines and devices, quick fixing of exchanged tools and their rational distribution, appropriate conversion preparation and the use of value analysis.