While the Metal Spinning industry is ploughing its way through making hundreds and thousands of machine spun products, you have to wonder what are the advantages and disadvantages of CNC (Computer Numerical Control) machines compared to manually operated centre Lathes?
CNC machines are very expensive to buy; however as the years move on the cost is decreasing due to the development of more efficient CNC models (and software). Manual lathes are cheaper to buy and require less setting up whereas CNC machines require you to either have somebody install and set it up or you can do this process yourself.
Size matters! If you are an SME (small to medium size enterprise) you may not have the space available for a CNC machine. Most models take up more than space then a manual Lathe. CNC’s can contain and collect unwanted debris compared to manual Lathes where the debris fall to the floor, making it a trip hazard and generally making the workshop look untidy.
CNC machines can be operated by one person. That one person can attend to more than one machine due to the machine producing all the work, with only a need to either change the tooling, replace a finished product with a new piece of material or to collect and dispose of material debris. Little training is needed for this one person to work the CNC machine. This is declining the need for skilled manual Lathe workers, putting people out of work, and threatening the industry with less people being taught in the art of manual machinery type jobs.
CNC machining is reliably 99.99% accurate, and can produce products four times quicker than on a manual Lathe. The other .1% is when the product dimensions can sometimes be off by up to 0.5mm, often this is due to the type of material, the temperature of the environment or the tooling being faulty; however this is a very rare occurrence. The machine is designed and programmed in such a manner that thousands of products with the same dimensions can be manufactured with complete accuracy and just with a single command. Even though the advantage to a CNC machine is that it can produce products with speed and accuracy, there are some jobs it can’t do, that a skilled worker can achieve on a manual Lathe. But the downside to this is that human error can’t product a perfect product every time.
The CNC machine can be operated 24 hours a day, all year round, only stopping for maintenances. At the same time, updating the software can improve performance and speed. Depending on the type and size of job the CNC is required to do; renewing the tooling can be both cheap and expensive.
Prototypes are often required by the client before making the actual product. This could be to make sure the product has been designed correctly and can be made to the exact specifications. Finding a fault in the design early in the product life cycle will mean the design can be altered and will save time and money. The CNC machine does have the software that can simulate prototypes, therefore eliminating the need to use the CNC machine to make a physical prototype. This is another way to save money and time.
There may be more positives for the use of a CNC machine, but it would be wise if a SME wants to invest in a CNC machine, to always keep the manual lathe process within the company and not always rely on CNC machines. Although they allow for a much faster and accurate production line and eventually it will pay for itself, there is always the possibility that It could break down, so a backup of manual Lathes can at least keep up with the constant demand of work should the need arise.
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