CNC router machining allows us to create accurate workpieces in a fraction of the time it takes to craft the same design by hand. If you have ordered something from a CNC shop or are planning a new project with your own CNC router, you will naturally wonder how long the whole process takes.
CNC router machining can take a long time depending on the size and complexity of the piece – anything from a few hours for a simple design to weeks for an intricate design on a 5-axis CNC router.
Below we will discuss some of the factors affecting how long the whole process of CNC router machining takes to give you an idea of how long you can expect to spend on any project you have in mind.
Why Does CNC Machining Take As Long As It Does?
CNC machining is much quicker and more accurate than working with hand tools, but it may still seem like a long haul to the uninitiated. As we mentioned already, there are many variables one must account for, especially with more complex pieces.
CNC machining requires preparation and programming, and the router itself will have an upper limit on how quickly it can work. In many instances, the program will have to be run at least twice – first, for a rough cut and, secondly, for a final finishing cut.
It is difficult to quantify exactly how long any given project will take. One also has to account for errors in the machining process, some of which are unavoidable. It may be necessary to carry out some of the finishing work by hand.
Complex Pieces Just Take Longer
The length of any particular operation on a CNC machine comes down to complexity in the end.
The more movements a CNC router has to make to complete a job, the longer it takes. For the simplest rectangular cutouts of thin material, you can expect the machine to achieve these cuts in a relatively short amount of time.
On the other hand, for more complex pieces where the machine has to cut recesses, steps, or bevels into a thicker workpiece, it may have to make dozens or even hundreds of individual movements.
The Secret Timesaver
One of the benefits of creating a project on a CNC Router is that it can be run time and time again. After all the kinks have been worked out of the program, you will be able to attend to other things in the shop like cleanup, putting a finish on other projects, preparing other projects for the CNC, and so on. The proven CNC program will not have to be watched the entire time it is running.
In addition, most CNC programs (I use V-Carve Pro) will let you batch out several copies of a project at a time. Once the initial program has been optimized, you can duplicate it and generate a new g-code file to run multiple copies at a time. While the machine time may be longer for this type of job, in the end, you have saved more time than running parts one at a time.
Preparation Is Key
This is a universal truth for just about any manufacturing process or project – the quality of preparation can make or break the results.
Preparing a CNC router for any given project will require adequate preparation. This involves designing the piece, cleaning the CNC router and work area, verifying that the router is in calibration, selecting the milling end piece, and setting the material in the machine.
Failure to carry out necessary preparations can have disastrous results. It must also be noted that one’s familiarity and skill at using the CNC router will impact how quickly this is done. Preparation should be second nature for skilled workers, and their valuable experience will preclude many novice mistakes.
The good news is that once you have a CNC program running flawlessly, that project can be run without errors many more times. Taking notes on what worked and what didn’t work for each project and storing them away with the project will assure success every time the piece is recreated.
CNC Router Machine Calibration
Calibration of any precision equipment is essential, and CNC routers are no exception. The machine must be routinely checked for accuracy to prevent waste of time and material.
CNC routers need to be calibrated at least every 6 months to ensure productivity is not lost. Where a CNC router has been moved from one location to another or is newly installed, calibration will also have to take place before any work can be done.
If you do not calibrate your CNC router, you will never produce accurate work with it. The calibration process requires either precision machinist leveling or more modern laser calibration to ensure that each axis is true. Even a slight deviation can have disastrous consequences.
It is recommended that if you do not have the expertise or equipment to calibrate a CNC router correctly, you should instead enlist the help of a local calibration company. This can save you a lot of time, material, and frustration in the long run.
Minimal Waste Design
Another reason CNC router machining can take so long because many users will try to use as much of the material as possible. This sometimes involves plotting and arranging multiple designs on the same piece of material for minimal waste.
Therefore, what may seem like a small and easily machined part can take a lot longer since it is machined along with many other parts. In reality, you are saving time by machining many parts at a time. Again, you do not have to babysit the CNC while these parts are being cut out. Go do other stuff (but stay nearby in case of some unexpected failure.)
CNC Router Machining Errors
While CNC router machining is far less labor-intensive and time-consuming than traditional methods of crafting, the equipment is by no means perfect. One must account for tool wear, equipment failure, and good old human error in the manufacturing process.
The truth is CNC router machining is rarely as simple as programming the machine, feeding it material, and pressing a button for a perfect cut. Often, there will be some adjustment and finishing work required to smooth out rough edges and produce a satisfactory workpiece.
Wearing Parts on CNC Routers
Nothing lasts forever, especially where moving parts on concerned. CNC routers tend to have a lot of different moving parts, and the wear on each of them can have a cumulative effect on the quality of work it produces.
While CNC routers are intended to give you many years of use, you may find wear on any of the following parts:
- Gantry – On a typical CNC router, the gantry wears over so slightly over time. A damaged or erroneously manufactured gantry will produce inconsistent results.
- Linear Guideway – The rails on which the gantry operates also wear slowly over time.
- Ballscrew – This part allows the spindle to move up and down on the Z axis.
- Spindle – Provides the rotary force required for cutting. It contains wearable bearings.
- Rack and Pinion – Provides the linear motion required to move the gantry or spindle across the X and Y axes.
- Cutting Bits – These are considered consumable items but nevertheless can impart a degree of inaccuracy through wear.
- Lubrication – A little preventive maintenance will go a long way to extend the life of all the parts mentioned.
While wear of 0.01mm on any given part might seem insignificant, the effects of wear add up. In more serious cases, you may end up with an error that makes your workpiece unusable, especially where you have overcompensated for wear and cut away too much material.
A CNC router requires careful maintenance and lubrication to ensure that it lasts as long as possible and, perhaps most importantly, cuts accurately. Worn bits need to be replaced, or the results will not be satisfactory.
Even if you are a highly skilled CNC machinist, you will occasionally encounter projects that require some TLC after the machining process is complete. In fact, most wood projects will require sanding and even tab removal. If you are going to round over or chamfer the edges, this is best done manually also – but can be done on the CNC if you have the right bit and skill set.
Some CNC router projects will require hand finishing with files, sandpaper, and other hand tools to smooth out minor defects and rough edges. Normally this doesn’t take nearly as long as the machining, but it can make a project take longer than anticipated.
CNC router machining often involves a lot more work than one might think. It’s not just designing and cutting; there is also important finishing work, as well as routine maintenance and calibration of the machine, that can make any given job seem to take longer. But, with proper planning, you will find that creating a project on a CNC – especially projects that will be made over and over – you will be saving a lot of time in the long run.
In the end, it’s almost impossible to tell how long any given job may take – any timeframe given is an educated guess at best.