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We shared some basic tips on improving machine shop efficiency in a recent blog with a focus on routine and philosophy. Today we will dive deeper into the machine side of things since in today’s shop the equipment performs most of the work. Here are four tips to increase machine performance in your machine shop.
Automation seems complex to establish and self-sufficient once installed, but the truth is the opposite. Automation requires consistent maintenance, assessment, and improvement. Setup can be phased in over time, automating one process at a time, and heavy support from both machine and software suppliers makes it achievable. It is important to take a step back from automation, however, when assessing efficiency to be sure basic manufacturing principles are understood and applied.
1. Lean Manufacturing Principles
Lean manufacturing focuses on removing non-value-added components from any process. It reduces waste and increases productivity through continued evaluation. The key attributes defined by Womak and Jones are 1) defining value, 2) mapping the value stream, 3) creating flow, 4) using a pull system, and 5) pursuing perfection. It lends itself beyond the shop floor to teams, inventory management, and inter-departmental relationships.
With a focus on machines and tools, the latest applications for lean manufacturing include ideas such as cellular manufacturing where similar parts are grouped to utilize the same equipment and production runs. This results in less setup time with continued use of raw materials and tools, for example. Inventory, machines, and tools can all be carefully located together on the shop floor as well.
The advances of data-driven Industry 4.0 may naturally resolve lean manufacturing principles such as value stream by virtue of their function, but it makes lean thinking even more important when planning production. Once automated, it’s easy to assume no improvements can be made. Be sure to be striving for that #5 perfection standard which may mean adding software, upgrading equipment, or simply re-assessing the tooling process for a given part.
2.Push Your Machines and Tooling Hard
The full value of CNC machines is often not tested on the shop floor. They truly are high-performance machines, like racecars, driven at normal highway speeds. The new 60,000 RPM machines are a big step up from 8,000 – 15,000 RPM just ten years ago. Integrated parts like spindles, cutting tools, servo systems, CNC and CAM systems all working together create a template for speed and precision that can make a dramatic change in efficiencies.
High-speed machining is more than simply speed. A CNC machine requires the appropriate support to calculate tool path and spindle speed to deliver the precision needed. It took some time to adjust to the idea of productivity increases with shallower, faster cuts, and now the same mental shift is needed to recognize the near impossibility of a crash with sensors, 3D modeling, and simulation software to program a high-speed machine.
A machine sitting idle is one of the biggest overhead costs to a machine shop. Not using it to its full capacity is a close second. The faster it can produce, the more work a machine shop can take on.
3. Use of Coolants
All this high-speed production does produce friction and heat. This results in warping of tools, inconsistent product finishes, and breakage. Using coolant addresses all these issues. Lubrication reduces the friction between the tool and the workpiece, it blasts away chips and debris that can impede the cutting process and reduces the build-up of heat directly at the point of contact.
Coolant use is a fine art, as are all processes in precision manufacturing. They can be compressed air, water, oil, synthetics, or semi-synthetics that make physical contact with the cutting tool. Air, for example, can also be used to clear chaff but does not offer cooling properties. Coolant is often an overlooked expense in a machine shop.
Both pressure and volume have to be considered in delivery. If the coolant is not delivered at the correct pressure premature tool breakage can occur. Too much coolant causes oily and dirtier machines and is simply a waste of resources. Too little will cause rust and heat damage from friction. Coolant can be delivered through air, mist, flood coolant, or high pressure, and should be assessed for each tooling operation.
4.Avoid Unnecessary Tool Wear
While using coolant properly and running your machines hard will result in greater efficiencies, you will want to avoid tool wear. Tool wear is the natural breakdown and gradual decline of a cutting tool due to regular operation. Every tool will experience tool wear at some point in its life, but you can work to limit it.
Tools are an expensive part of CNC machining and are often customized. Excessive wear will show inconsistencies and affect the quality of your workpiece. Tool wear can also lead to failure, which in turn can lead to serious damage, rework, and scrapped parts. Regular maintenance should address the assessment of tools. Utilizing intelligent software can predict failure rates for precise maintenance scheduling.
Tool chipping can be prevented by reducing vibration and chatter. Coolant and high-efficiency tool paths will prevent abrasion. And thermal cracking can also be avoided by temperature control with coolants and the addition of proper coatings to an end mill. Complete breaks are caused by loose tools or work holdings, improper speed and feed rates, or inappropriate depth of cut. These can all be addressed with software simulations or careful calculations by machinists.
Your Machine Performance
Addressing efficiencies in a machine shop is an ongoing job and an important one. Wasted material and broken parts can easily eliminate any profit from a job. These four tips to increase machine performance are part of larger production assessment that includes people, processes, and inventory. Often, machines are the easiest place to start because those efficiencies can be identified the easiest. Take the step to address your machine deficiencies for immediate results to encourage further assessment in your machine shop.