Time is money in the production business and the more you waste, the more you lose. The Single-Minute-Exchange of Die (SMED) methodology may allow you to successfully implement a lean production process in your injection molding business, and when combined with a progressive mold maintenance program, allow you to reduce the time needed for changeovers.
Lean manufacturing aims to eliminate unnecessary waste during production, and uncovering ways that will add value by eliminating or decreasing other processes or variables than can adversely effect production.
With the rising cost of transportation and raw materials, it has become increasingly important for injection molders to produce a wide variety of products. With that product expansion, the need for efficiencies and cost reductions has generated a lot of interest in the lean method.
Potential Problems in High Variety Production
- Lengthy and difficult set up procedures.
- Expensive, high-tech machines are required to increase production capacity and flexibility.
- Waste arises out difficult changeovers, lack of adequate maintenance or equipment not being ready when needed.
SMED (Single-Minute-Exchange of Die and Maintenance
Globalization and Just-In-Time models have increased the need for production of smaller lots on a more frequent basis. This shift in format requires accelerated set-ups to maintain flexibility, to meet customer demands, and to remain competitive.
SMED allows you to make the necessary reductions in changeover time to achieve a just-in-time pace. The practices under this system achieve machine changeover in less than 10 minutes (single digit minutes) thus reducing the time during which production is down. The SMED approach does not only just reduce changeover times but also the overall labor involved.
The goals of SMED are:
- Reduction in inventory
- Reduced changeover time
- More efficient changeover process
- Flexibility for reduced batch/lot size
- Improve flexibility in equipment usage
- Reduce impact and downtime on equipment
- Meet customer demand
SMED involves certain steps, with a basic overview as follow:
- Elimination of Non-Essentials: Observe and record the areas where change outs are required, then eliminate all non-essential activities where possible, especially duplication. By eliminating non-essential activities it is possible to speed things up and reduce waste.
- External Set-up: Get all the materials and supplies to be used in place so that they are available when required. Some things to consider for this include: color code all items needed, create checklists and develop and maintain uniform standards and procedures
- Internal Set-up: Replace complex tools where possible with more simple equipment to prevent unnecessary waste. Use functional jigs and fixtures, levered or one-turn fasteners, preset guides, pins and notches. Remember the goal is to work efficiently but still but also effectively.
- Measure: The SMED approach entails change, but to know if you’re on the right track it is vital to measure business performance every time. It is a successful way of knowing if improvements are being made or not. Based on the results obtained, corrective or proactive measures can be taken. Consider the time lost/wasted as the benchmarks you will need to improve upon.
Benefits of Equipment Maintenance
The SMED system also requires proper maintenance of tools and equipment. When equipment is well looked after, it is more reliable. It will result in production efficiencies and lower costs due to fewer breakdowns and equipment downtimes. Also, with an effective maintenance program, equipment required will be available as and when necessary reducing wasted time and high costs due to idle equipment and staff.
It is also imperative that molds are stored properly to ensure optimal performance and longevity. Instead of leaving it on the floor or on pallets where it can sustain damage, it is best to store molds in a designated storage area or if possible on shelving or racks. Furthermore, it is best to use rust preventatives and grease that require little or no pre-production cleaning for start-up.
Many companies treat mold maintenance as an after thought, and have yet to explore how new products (like the Nanoplas line of mold maintenance products) can have a significant impact on their set-up and speed to press times. These gains in production efficiencies when combined with an approach like SMED can have a real impact on the bottom line.
To learn more about how the integrated family of Nanoplas products can help reduce scrap, increase production efficiencies and save time for your injection molding operation, contact us today!