CNC Machines are Money Making Machines!
Desktop CNC machines or non-industrial or commercial units are viewed as toys. That is far from the case. CNC machines provide an individual or shop with the ability to bring new capabilities to the shop that they would not be able to before. In addition to completely new opportunities and products, a shop or company can add additional value to their current products. Increase precision, engravings, designs, production work, etc. A CNC machine should be valued as advanced technology just like a powered table saw was back when the handsaw was the only alternative. CNC machines will not replace all aspects of your shop but will aid a shop in becoming more efficient, bring new capabilities and products to their customers, and provide added value products that maybe your competitor is or is not doing.
Custom Outlet and Switch Covers
We see in homes all the time, whether they are mid level or higher end homes, the options for outlet and switch covers are vast but also few and far between. If you or the client wants something that isn’t wood, well they we can’t help them (sorta). If they want something out of wood or another material we can CNC, our opportunity is knocking. This biggest thing we see in high end homes, is folks want wooden outlet and switch covers but the selection of the big supplier is generic and doesn’t come from the same supply or region of wood the homes trim or cabinetry came from. With the power of CNC machines, a shop that does the trim and/or cabinetry can now offer nearly perfect matching outlet and switch covers to their customer. This is a value added product that was not obtainable before and instead of marking up a product in a catalog, we can offer it to our customer utilizing a piece of machinery that can work while we work on the main product that they hired us for.
Raw Stock to Beautiful Covers
The process isn’t labor intensive at all. Most likely someone that buys a machine that is capability of “production” work will have the machinery to mill the material to the required 1/4″ (.25″) thickness. The beautiful thing is we don’t have to get it exactly to .25″. If our material comes out of the drum sander at .27″ or .30″, we can adjust that in our CAD/CAM program. Once our material is ready, we can head to the CNC machine. But lets go step by step in how we went from raw stock to beautiful covers.
CNC machines are controlled by computers. The computer is controlled by the G-code (CNC language) that you design in your CAD (Computer aided design)/CAM (Computer aided machining/milling). A CNC user needs to design their product in a program. That program is going to generate g-code based on the tool paths that you described. We put out a video on the CAD/CAM for the outlet and switch covers. YOU CAN CLICK HERE TO WATCH THAT VIDEO. With the g-code ready, we can prep our material.
We started with 5/4 walnut and resawed it at the bandsaw. We then ran it through the surface planer and drum sander to get the thickness to .25″ without going under. As we mentioned earlier, if we don’t hit it exactly, we change our material thickness in the CAD/CAM and regenerate our G-code.
Holding Down the Material
There are a variety of ways to hold down material on a CNC machines. From simple top clamps to vacuum tables, that are a plethora of ways to secure your material to get the job done. As one gets more and more experienced with a CNC, they tend to pick one way over another based on different variables. Some of these variable can include: size of the part, type of cutting operations, and how aggressive does the programmer want to get with their speeds and feeds. For this project, we decided to use double sided tape. The material we are using is thin and would need a bunch of clamps around the edges plus we have through cuts. These cuts will release parts and possible cause damage to the parts or the bit. We want them secured to minimize the chance of them moving. Double sized tape gave us the best opportunity to have a successful CNC routine with minimal risk to the material and bit.
Loading the First Bit and Operation 1
Our first opp or operation is going to be with the .25″ bit. This bit is going to make the large pocket while leaving a small post in the middle to support the cover while it is being secured. It will also surface this post to bring it to the correct height.
We need to load the .25″ end-mill into the spindle and tighten with the wrenches. We will then use the zeroing touch plate to set the z axis. In our CAD/CAM video, we set the zero point to the surface of the spoil board and not the top of the material. That is because we had through cuts. Zeroing to the top of the spoil board ensures your through cuts will go all the way through the material.
We then load the file into the control software and hit “START”.
Loading the Second Bit and Operation 2
When operation 1 is completed, we vacuum the table off and remove the .25″ end-mill and install a .125″ end-mill. This will be used for operation 2. In this Opp, we will make the cut-outs for the actual outlets, drill the mounting screw hole, and then make the profile cut to actually cut out the cover. Even with a small end-mill, we are able to be pretty aggressive with our feed speed and that is due to a solid speed and feed relationship. We are making a healthy chip and we don’t hear chatter from the bit.
Chamfer at the Router Table
With the CNC operation completed, we can remove the double sided table and run them through a chamfer bit at the router table. This subtle detail provides a nice elegant shadow line and also makes the plate look thicker than it actually is.
Screw Hole Countersink
The CNC machine was machining on the back side of the cover. It would be impossible to apply the chamfer without coming up with a holding and alignment jig. This sometimes is necessary with some operations but for such a simple task. We head to the drill press with a counter sink bit in it. After some testing and trial and error, we set our hard stops and quickly batch them out!
Quick Hand Sanding
The finish off the CNC and router table are pretty good. We use sharp bits and proper speeds and feeds but a quick touch with some 220 grit sand paper makes world of difference to wood. We use a sanding block and a 6″ ROS 220 grit paper to make quick work.
3 Coats of Lacquer
These outlet covers need protection and also to make the grain pop. For this small job, there is no need to bring out our HVLP gun. We use a rattle can of semi-gloss lacquer and hit it with 3 coats. We sand with 0000 steel wool in between coats for a baby smooth finish that is sure to please the eye and occasional touch.
The results speak for themselves. They are beautiful! The cover geometry fits perfect. The chamfer adds a wonderfully simple detail while the lacquer makes the grain pop. We used walnut for these covers but you can literally use any wood plus other composite materials. Anything your CNC machine can machine, you can make an outlet cover.
Our client was happy and our shop was profitable.
How much money did we make?
For these 18 outlet covers, we had them completed in 3.5 hours. That includes material milling, CNC time, hand work, finish and drying time. Plus, during the CNC drying time we were doing other jobs in the shop. Depending on the machine you choose and how much it costs and maintain, you will be able to come up with a dollar per hour cost of running the machine. This includes the initial capital, maintenance, tooling and bits, electricity, etc. You will also have a shop rate that determines how valuable your time is. Depending on your skill, demand, and abilities, this can be a pretty big window.
For example, we will have $20 per hour cost of running the machine and a $50 per hour as a shop rate per man. We had an two hours of CNC design time, milling, and hand work. Our CNC time was approximately an hour and a half.
CNC Time = $20 x 1.5 = $30.00
Labor = $50 x 1.5 = $75.00
Material costs = $40.00
Total cost = $145/18 covers = $8.05/cover.
Depending on your area, clientele, and demand, you certainly want to tack on to this number to grow your business. We charge $12 for a single outlet cover. This allows some room in our calculations as well as puts some money in for our other machines and business expenses.
Keep in mind, this price is for Walnut hardwood. If you use any other material, your material costs will go up or down. If a client wants a more complicated design, we may or may not adjust the price depending on if it adds another operation or significant amount of labor/machine time.