Selecting CNC equipment isn’t a process you should rush. There are so many variables involved, so to make the right choice, you’ve got to consider them all carefully.
To help you do this, we’ve created a straightforward guide that goes over the main things you need to know about when buying a CNC mill, particularly if you intend to use it in combination with SolidWorks.
Consider the machine’s construction
Durability is an important consideration depending on the types of projects you’ll be taking on and the number of work cycles your CNC mill will go through in a given period.
For lighter-duty use, you might find that a mill made with lighter materials, such as metal alloys or even composites, will be sufficient. For heavy-duty workloads, sturdier gear constructed from tougher materials such as steel and even cast iron will suit your needs.
Check the precision potential
Getting to grips with tolerances is essential for any designer or engineer. Understanding how these apply to CNC mill choice is the next step.
The more precise the machine, the closer it will get to follow your original design, and the better suited it will be for particular applications.
This, of course, comes at a price, as mills that deliver tighter promised tolerances are costlier than those that don’t hit the same levels of precision, even if the difference is a few thousandths of a millimeter.
Assess the speed
How rapidly a CNC mill can fulfill a given cycle of operation will vary, and it’s not simply a case of choosing the fastest bit of kit that’s within your price range because precision again rears its head here.
Higher speeds can lead to less precise performance, so if you want accurate recreations of your SolidWorks projects every time, a slower alternative might be best, especially if you’re not trying to pump out large volumes of components in a short timeframe.
Speed is also impacted by the materials being interacted with, as well as the complexity of the design and the nature of the tooling. Once again, it’s a case of having your unique requirements at the front of your mind when comparing options.
Analyze the size of the equipment
The scope of a CNC mill will determine the types of workpieces it can accommodate. You need to balance this against the amount of space you’ve got available to accommodate the machine on-site because you don’t want to pinpoint an apparently ideal bit of equipment only to find that it won’t fit.
Don’t get overawed by the idea that bigger equals better. If you’re mainly going to be using the mill for rapid prototyping, a compact model will work well and will be more affordable to boot.
Buying a used CNC mill
With the variety of CNC milling machines available on the second-hand market, there’s no need to purchase one that’s brand new, especially if you don’t have a whole lot of wiggle room in your budget.
There’s a certain amount of snobbery surrounding used equipment, of course, but the reality is that if a mill has been put to use in the past and also received plenty of maintenance and attention, it won’t just be cheaper to procure but could also be more reliable as a result.
At this point, it’s worth discussing pricing, which is, of course, as variable as the feature sets and specifications of the mills on the market right now. The smallest mills can be picked up for $30,000, while the largest or most cutting-edge will sell for as much as ten times that amount.
Settling on a budget that you’re comfortable with before you start searching for a CNC mill is sensible. You’ll avoid overstretching yourself and won’t be disappointed in what you can afford.
Exploring axes of operation
The one thing we’ve neglected to mention so far is a CNC mill’s capabilities when it comes to the way it can manipulate the tooling.
Simpler mills may only have a couple of axes of movement available to them, while the flagship examples can boast four or five axes of operation.
If your SolidWorks designs are especially complex, then a multi-axis machine will clearly be a must-buy. Either that, or you’ll need to break down component designs into smaller segments that can be more easily produced using machines at the more basic end of the spectrum.
The other costs of choosing a CNC mill you need to take into account
It’s not just the upfront expense of the individual piece of equipment you pick that comes into play in determining whether it’s the right choice. You also have to be aware of what it will cost to get it shipped to your premises and installed in situ, for example.
There’s also the factor of the ongoing running costs, such as those that come from powering the machine, which may be a concern if you’re looking to save energy, as well as the repairs and maintenance jobs that will be needed over time.
Getting the training needed to use a given CNC mill effectively is another expense to factor in, assuming that you are not already an expert in a particular type of equipment in this category.
Final thoughts on choosing the right CNC mill
The reality is that anyone who’s new to owning and using a CNC mill should almost certainly consult with a specialist before pulling the trigger on a purchase.
Even if you’re a wiz at designing in SolidWorks, that doesn’t mean it will be a breeze to convert this into a tangible object using a mill, no matter how much you spend to acquire it.
It’s perfectly possible for home hobbyists and businesses to bring a CNC mill on board and have a productive, profitable time using it. But going in with a realistic idea of what the costs will be and how much you’ll need to learn to master it will allow you to sidestep the possibility of disappointment in the long run.
