As the custom parts market grows exponentially, new machine shops are constantly emerging and so we have a wide range of CNC shops to choose from. Of course, we all want the best quality for our pieces. So, if I were to choose a CNC shop near me, I would look for one that has a competitive advantage and offers the best value for money. This includes high-quality workmanship, fast processing times, and on-time delivery. For a facility to achieve this competitive advantage, among other things, it must incorporate efficiency into its processes, and one of the most established and effective ways of doing this is through the application of lean production principles.
Adapting Lean Manufacturing Principles in a CNC Shop
What is Lean Manufacturing in a CNC workshop?
When we talk about lean manufacturing, we first mean maximizing the production of a CNC workshop, minimizing the waste generated during the production process. This method dates back to the best practices that Toyota used in its production line in the 1930s. Its main objective was to eliminate waste in its operations.
As this method has evolved since its discovery, industry experts have identified eight main categories of industrial waste that can be abbreviated as DOWNTIME: defects, overproduction, waiting times, underutilization of talent, transportation, excess inventory, wasted motion and overprocessing.
1. Defects
In a CNC shop, this may include scrap due to dimensional inaccuracies, undesirable surface finishes, and other defects in the machined part. These defects are usually caused by several factors such as: Examples include inadequate machining parameters, machine malfunctions, poor quality tools, uncalibrated instruments and poorly planned machining processes.
2. Overproduction
This industrial waste arises from an oversupply created by blind parts production, so that parts produced exceed demand. Sometimes this is due to poor planning and uncoordinated parts ordering.
3. Waiting time
This is wasteful because unused time could be used for more valuable production steps. Examples of this include production stoppages due to lack of materials and machine failures. Wait times in production can be caused by poor planning, unforeseen machine failures, and more.
4. Failure to use talents
This also includes not effectively utilizing an employee's talents and skills.
5. Transport
This type of waste is characterized by excessive transport from one process to another. In other words, transport waste is the absurd steps of a process that can be eliminated or improved by a more efficient step.
6. Excess inventory
In CNC machining facilities, this waste amounts to overproduction, where excess inventory can result in losses for a CNC shop. Remember that manufactured parts that are trapped in a warehouse do not generate revenue for the company and are therefore considered industrial waste.
7. Loss of movement
This also applies to the unnecessary movement of resources that do not add value to the product as a whole. In a CNC shop, this includes the non-strategic placement of various tools, materials and workstations.
8. Overprocessing
In the production of machined parts, excessive processing involves carrying out unnecessary processes that are irrelevant to customer needs. This is often the result of a poorly designed editing process.
These various wastes led us to the main fundamentals that machine shops can use when implementing lean manufacturing. And these are:
7 Ways a CNC Shop Can Implement Lean Principles
1. Maximizing tool efficiency (tool selection)
Tool efficiency is a critical factor for a machine shop because this single factor can determine the quality of parts produced by a CNC machine. Selecting the right tools is important to ensure high cutting quality and thus minimize the number of defective parts due to tool misuse.
2. Intelligent handling of machining parameters and machining processes
Production engineers carefully plan their parameters (e.g. feed rate, cutting speed, depth of cut, etc.) to obtain maximum benefit from the CNC machine, material and tools. In addition to parameters, it is important to design the most effective arrangement for different machining processes. This minimizes waste due to defects, movement and excessive processing.
3. Consistently perform periodic and preventive maintenance
Machine downtime is by far one of the main reasons for unnecessary production line stops. Therefore, careful adherence to scheduled maintenance is mandatory. Unanticipated downtime is significantly reduced through regular maintenance and inspection of various equipment, resulting in reduced waste due to waiting times, defects and unused talent.
4. Just-in-time (JIT) production
JIT is achieved through intelligent planning and scheduling of various resources. Another main reason for unnecessary waiting times in a CNC workshop is the unavailability of raw materials. To avoid this, planners develop strategies for the most effective methods regarding input, processing, and output of various resources.
5. Increase productivity
It is important to strategically plan the organization and placement of the various instruments needed in the production of CNC parts. Something as simple as applying 5S (Classification, Organization, Cleaning, Standardization and Maintenance) in a work environment can drastically improve the organization of a workflow. This avoids waste associated with movement and unused resources.
6. Strategic plant planning
In a CNC machine shop, equipment planning is one of the most important issues that must be taken seriously to avoid unnecessary waste caused by excessive transportation. Example scenarios would be: Racks for raw materials should be placed close to the stamping operations, Machines are arranged so that the part can be easily transported to the next machining process, Finishing equipment is placed close to the processing area packaging.
7. Continuous improvement initiatives
Lastly, it’s about maintaining CNC shop best practices. In the long term, CNC shops that continuously improve their processes are the ones that can provide the highest quality parts with promising delivery commitments.
