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The constant balance of efficiency and quality keeps CNC machine shops looking for new machines and software to provide an edge over the competition. Many improvements can be made by simply reviewing current operations. We always recommend a full assessment of optimizing what you have before you buy new equipment because procedural inefficiencies will always follow you. The use of lean manufacturing for CNC machining can provide this overview, and not just one time. Lean manufacturing is a business culture where equipment, processes, and people are assessed regularly with efficiency and customer satisfaction married seamlessly.
Lean manufacturing principles are employed in many industries including healthcare, customer service, automotive, and quality control processes. The principles can even be employed in your home office or small business. Toyota is known for developing this system of eliminating waste in its manufacturing process. It grew and has become adopted globally operating as the Lean Enterprise Institute. In its simplest form, it assesses a process and eliminates anything that does not add value.
This sounds simple on paper, but the assessment is the biggest hurdle. Breaking down each step in a process can be difficult especially when it has been performed the same way for a long time. It can be hard to see a different way. Here are 5 steps to embrace lean manufacturing for CNC machining.
Involve Staff
The best results for any change come from receiving input from the staff. They understand production realities the best because they have hands-on knowledge that engineers and designers do not. Staff can be viewed (or video-recorded) during production to assess processes. Staff need to be ensured this is not an audit of their skills, but to determine ways to make their jobs easier. When staff embraces the process, they may contribute observations and add to the critical thinking needed to maximize each step in the CNC machine operation. They may note items such as duplication of efforts, or access to needed tools impeding their productivity.
Utilize Software
Value mapping is the process in lean manufacturing that analyzes current processes to improve flow. With the additional features available in machining from Industry 4.0 this can be automated. Think of how the approach to machine a part was once pencil and paper and the knowledge of a master machinist. This grew to include automated processes that could drill or chip multiple passes and improve efficiency. Now the IIoT (Industrial Internet of Things) introduces software that can assess a CAD drawing and determine the most accurate toolpath. Sensors and feedback systems are also available to accurately map the success of the process making room for further improvement. Once the manual processes have been fine-tuned to maximum output, this type of software is the next step.
Reduce Material Waste
While the entire process of lean manufacturing focuses on waste, material waste is a stand-alone in terms of priority. Material waste during milling processes is the first area of consideration. Software, as indicated above, will help with this task. Chaff and other waste, such as coolants and lubricants, must also be addressed. Introducing a centrifuge machine can remove coolants from scrap metal chaff producing higher prices from scrap metal sales and less space occupied on the shop floor. This also reclaims cleaned cutting fluid to be re-used avoiding both disposal costs and purchase of new coolant. Fluid life can also be extended dramatically with the use of filtration.
Plan Flow
Each time an operator leaves their station to retrieve raw material, a tool, or remove scrap is time not producing the part. We address organization on the shop floor in this article to improve flow. Lean manufacturing takes a direct look at each operation and station to assess those movements and rework them into the most efficient configuration. Lean product and process development (LPPD) is the term that applies to the overview of all processes on a shop floor working in harmony. Flow considers the need to leave a workstation, and the distance traveled to retrieve parts or tools. It considers the entry point of raw material through to warehousing or shipping the final product and minimizing waste on each step of the journey.
A typical example of a flow problem is the addition of “lights out” manufacturing. Thousands of parts may be run overnight, but a bottleneck occurs the next morning as manual quality inspection is needed to release parts for further processing or shipping. Analyzing the flow would address this with the addition of sensors, perhaps, on the CNC machine to measure quality through visual sensors while in production.
Lasting Effects
One of the most important factors of lean manufacturing for CNC machining is to continue to strive for perfection. Some experts propose that lean manufacturing needs to be addressed at least 6 times to reach its leanest form. Lean needs to become part of company culture where everyone benefits from the contributions they make. It can be contagious and extend beyond your business to your suppliers and customers as they see the added value.
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CNC Machining has been stated to be one of the most versatile methods of production, but converting it into a cost-effective one requires something more than mere machinery that is optimized. One factor that goes unnoticed most of the time is the material selected.
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