Any company in the machining industry has to incorporate Lean Manufacturing in their business and process plan to survive these days. To put it in simple terms, lean manufacturing is the production practice of being efficient by eliminating any ‘waste’ in the process plan. Though they may not call it this, all companies strive to be lean because it makes their customers happy, and ultimately, more money.
Although there was seven original “Wastes” involved in lean manufacturing, we’ll look at eight of the most common ones in a machine shop. Most of them are simple, but it can take a lot of work and orchestrating to implement them all. There is no perfect company that has it all figured out. There is always room for improvement, which is why employers seek new ways to lean out their manufacturing process. The acronym for this practice is “DOWNTIME”. Now you could just look this term up on wikipedia, but it won’t give you a real perspective or example of what it means. Those are just general illustrations in the manufacturing industry, but working in a machine shop may produce different scenarios.
If bad parts are made, it takes more time to either re-work it or make another one. More material, more machine time, more tooling wear, which can add up to almost double the cost of a part. The machine shop pays for this and not the customer, and that is why it is on the list of big “wastes” that companies try to eliminate. We are only human, so mistakes do happen occasionally, but the goal is to decrease the percent of defective parts.
I believe that this one can go either way, but if space is expensive, then overproduction is definitely considered a waste. If you make extra parts for a customer, it costs more time to make them, and the excess supply of parts costs more to store because it takes up more space in between machining and shipping, plus the time it will take for the customer to order more. If something happens to the customer and they discontinued that part or went to a different vendor, your extra inventory has now turned into a complete waste of money.
There’s two ways you can look at this; the parts that are waiting, or the machinist that is waiting. This happens whenever you have stock waiting to be cut or for operations on a machine. There is usually a waiting time in between finishing the parts and shipping. This takes up valuable time, as well as space. Although it may not seem like a big difference if parts are waiting an extra day or two to be worked on or shipped, the quicker you get the parts out your door, the quicker you can move on to another part/order.
This should be an easy, but too many employers miss it. If you have an employee that is skilled multi-axis machining and/or programming, putting them on a grinder or running simple mill parts is a waste of talent. Even if they need a little more training, it’s much more efficient to move that employee to the more complicated work instead of hiring another person, which you may have to train-in anyway.
Transportation is all of the unneeded movements of parts and materials. The shortest route from point A to point B is a straight line, anything else is wasting time. While it’s not always possible to do this in a machine shop, the shorter the distance parts and material have to travel the better.
This is similar to overproduction because having too big of an inventory takes up space and takes more machine time to run. If you’re making more parts than the order requires, it is considered wasteful inventory.
Much like wasteful transportation of parts, a machinist should reduce wasteful motion as much as possible to be efficient. If you’re setting up a job, all the tools should be set-up and ready to go or on the workbench next to the machine. This can be done during cycle time of the previous job to save time. When loading and unloading parts in the machine during production, as well as part deburring, having everything close by or within reaching distance will reduce motion and save time in the long run.
Like mentioned before, time is the biggest money breaker or maker, and if you’re spending too much time trying to perfect parts or orders when it is not needed, then you’re wasting time. If you have wide open tolerances on some or most of the part features, spending extra set-up and/or cycle time to try and get it right at the nominal number is waste. As long as all of the parts are within tolerance of the blueprint, they’re good. If the part doesn’t go together during assembly or function properly, it’s that customer’s job to fix the print, not the machine shop’s job.
Now, how can YOU as a Machinist benefit from all of this? This can help boost your reputation at your current job, as well as your resume. The harder you work at being more efficient, the more your boss/foreman will notice. This may result in better raises, a promotion, or benefits in various ways.
Although not all of these factors directly relate to you, suggesting them to higher authority may give you better recognition in the long run.