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It is generally accepted that CNC machines are an effective way to manufacture many materials, mainly wood, plastic and aluminum. Therefore, once you decide to use CNC routers in your future, how do you start to narrow your choices to those that suit your business?
According to my experience, the standard can be divided into 3 main themes: machine, software and support. It is obvious but worth mentioning that having a great machine but programming software that does not fully utilize its capabilities is a waste of resources. On the contrary, having excellent software that can make efficient programs but running on a machine that cannot accurately execute the code will also waste time and money. In the end, great software and great machines are not great unless you can get help when you need it.
In many shops, the investment in CNC machine tools is second only to construction costs. But commoditization occurred at the low end of the spectrum. The cost of owning a simple machine is now less than $5,000, which makes CNC more affordable than ever.
I decompose the range of machine features into the "physiology" of "skeleton", "heart" and "brain". Bones are the structural components of the machine (frame, bridge, and bolt components). Is the frame welded together or bolted together? The welded frame does not need to be re-squared regularly. If it is welded, the stress can be eliminated. Check the structure of the frame. The old adage applies. The heavier the weight in the frame, the better the longevity.
Look at the bridge. Overweight here may be harmful, but steel is much better at damping vibrations and is harder than aluminum. And pay attention to the bridge legs, all cutting forces and all power generated by the movement are borne by the bridge legs. Finally, ask about the parts that are bolted to the frame. All machine tool manufacturers purchase components such as linear guides, rack and pinion and ball screws. All component suppliers have different sizes and grades, which will translate into the usable life of the components.
There are other features that need to be checked about the frame, the most important of which is the fixture. How will you clamp the workpiece during machining? Work table design needs to include a workpiece clamping system.
If the frame of the machine is bone, then the main axis is the heart. For milling spindles, you will usually find 2 types, with and without automatic tool changer (ATC). You must determine the number of different tools required to complete the job and match the spindle type to the job. But CNC control changes the function of a single tool. For example, you can use a 5mm router bit to drill a 5mm hole, then circular interpolation to make an 8mm hole, then use dado, and finally cut ¾ of the perimeter of the side of the plywood cabinet (use 2 or 3 times). This is called the 5mm strategy, and although it is not the "ideal" method for cutting nested cabinet parts, it is much faster than manually. It is certainly suitable for small shops with limited budgets, and it is easy to make several kitchens every month. However, more production will require the use of different tools for each operation, resulting in faster cutting and reduced cycle time.
There are basically two types of ATC spindles ISO 30 (or BT30) and HSK63. The difference lies in the way the tool holder is fixed in the spindle. Although ISO works normally, the HSK63 connection is stronger. Speaking of capacity, there is a simple calculation. Each 4 x 8 pieces of material can hold all the components of 1 to 2 cabinets. It depends on the size of the cabinet and the construction method. For example, stretchers use less material than solid tops. Depending on the tools used, the power of the spindle, and the stiffness of the frame to withstand the cutting force, the pure cycle time for cutting nested cabinets may vary greatly. As an example of using an ATC machine, we assume that the actual cycle time is 7 minutes, and then add 3 minutes for loading/unloading. Then the time from floor to floor is 10 minutes. This means that 6 to 12 cabinets can be produced in 6 cycles per hour. If a "typical" kitchen has 20-25 cabinets, then conservatively speaking, all parts can be cut in about 4 hours (6 cabinets per hour x 4 hours = 24 cabinets). That is 2 kitchens per day, or 10 per week. If you need more capacity, please consider adding a drill seat or increasing the spindle power to speed up the cutting speed. A drill block can save about 1 minute per sheet of paper. You can also consider strategies to reduce loading time. The dual table machine allows you to handle one table while loading/unloading another table. There are also some automatic devices that can completely eliminate the human factor of loading/unloading.
Finally, I call CNC control the brain of the machine. In the simplest definition, the function of control is to keep the machine on a specified cutting path. As the cutting speed increases and the accuracy requirements increase, the requirements for control will also increase. I must admit that there is a personal bias here, and I like the control of big companies behind it. Like many others, I feel that I can solve any mechanical problems (maybe with the help of my local mechanical workshop). But when it comes to electronics, if something stops working, I need to order a new one. I like the idea of the resources of large multinational companies to ensure that I can use parts when I need them.
I will also include drive motors in the brain topic. There are two types of drive motors, stepper (usually open loop) and servo (with feedback, closed loop). Stepper motors are used for lower cost machines, while servo systems are the choice of machines where performance is a key consideration.
For example, if you plan to machine MDF gates, the repeatability requirement to eliminate steps between tool paths may be in the fourth decimal place (.0005"). Both your machinist and electronic equipment need to complete tasks to produce these results. "Open loop" control will encounter difficulties in such work. Therefore, it is not common to understand that it is not common to obtain control selection due to the work necessary to combine the control with the machine, so when you consider the choice, this should be a major issue. theme.
Some type of software is needed to write a program to run the machine. When it comes to software, it is more of a choice than a statement of fact.
I may use software brands that I find easy to use and intuitive, but for others, it feels counterintuitive and difficult to use. Everyone has their own "logical flow" in their early adulthood. If the software requires you to enter in a seemingly logical way, the software seems easy to understand and very suitable. Conversely, if the required input is out of sync with your logic flow, it will feel clumsy and difficult to use. There is no problem with this software, but it is not a good software for you.
In other words, you need to interview several software and find one that seems meaningful to you. Then remember that it only works when you learn to use it. Buy enough training to keep you going, don’t “get what you pay for” on training. Some additional training in advance can prevent a lot of frustration and scratching of parts.
Support for the machine is as important as the machine or software. It starts with learning to operate the machine correctly and safely, but it should go far beyond the basics.
Understanding the countless parameters that contribute to successful and profitable machine tool integration involves many factors. Tool optimization, solid wood processing technology and fixed small parts, to name a few. Support should also include having the required replacement parts and technicians to ensure that your machine is in good operating condition. In short, get help anytime, anywhere.
Today, many CNC companies can access your machine via the Internet and can troubleshoot the component level and then install a part for you overnight. But remote troubleshooting is not a panacea. As we all know, the more complex your machine, the more likely it is to require professional and technical personnel from outside the company. Unless you happen to be operating on the streets of your CNC machine tool company, it will cost money to bring this technology to your front door. Generally speaking, simpler machines are easier to repair and more reliable. I know this article is very brief, so I am happy to elaborate.
Author: Tom Galzin, is the sales and purchasing representative for New CNC in the Netherlands, Michigan. For more information, please call (616) 994-8844 x6, tom@newcnc.com or visit NewCNC.com to contact him. Read more on WoodworkingNetwork.com.
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