Tech Today: CNC Machining for the 12-Volt Industry

MACHINING FOR THE 12-VOLT INDUSTRY

WORDS BY JOEY KNAPP

Last month, we got a glimpse into 3D printing thanks to the very knowledgeable Brian Schurg. Hopefully, Brian answered some of the questions you had about 3D printer technology and how to integrate it into your mobile electronics business.

This month we will continue looking into the more popular maker tools being utilized by 12-volt fabricators. This segment on CNC machines is written by yours truly. I am the new owner of a hobbyist CNC!

Exploring the Options: From 3D Printer to CNC

I have known about 3D printers, CNC and lasers for quite some time. In recent years, my Facebook feeds have been dominated by my 12-volt friends making all sorts of game-changing items with their new automated tools. It’s very exciting to see how our industry is advancing, but also a little discouraging for me because most of these technologies were financially out of my reach.

The 3D printer was the most cost-effective option, and the prices continue to drop. I wasn’t sure, however, that I could see one of those fitting into real world everyday use in my shop. The main issue was the printing time. I knew plenty of friends with them, so if I ever really needed something printed, I could probably arrange it.

The other challenge to a 3D printer was the software. I started learning Fusion 360 and realized it would be a steeper learning curve than I really had time for at this point.

Lasers are another cool tool. There were some more affordable options, but it seemed you got what you paid for. The more inexpensive lasers were either from companies that may have questionable support, or didn’t provide enough wattage to cut what I wanted to cut. I knew I could handle the software for a laser, but there was no value at the price point I could afford.

The final option was a CNC. I could see myself getting regular use out of it. I always thought it would be great to have box designs saved, and cut them at the click of a button.

A few years ago, the owner of Jacksonville, Florida-based Audio Designs & Custom Graphics, Darren Fettik, invited me to his facility to take part in the training for his new CNC. Darren had recently jumped feet-first into production fabrication with the purchase of a Techno HDS 4896. It was exciting to spend the day learning about the capabilities of that fine machine. This was my first experience seeing a CNC in action, and it was certainly impressive!

The problem: Your first exposure to something this superior is that the bar is set very high. After leaving Darren’s shop, I knew the way to go was a four-foot by eight-foot machine. In my mind, that was truly the only option for a mobile electronics fabricator. As a result, I had yet again priced myself out of a new fabrication tool.

Changing the Way We Think About CNC

I continued with my rudimentary caveman techniques of routering by hand, and sanding things.

A few years ago, I started seeing the items one of buddies, Christopher McNulty, had been creating. He was making smaller pieces, and did not have a full-sheet CNC. He had purchased a smaller desktop model. I initially disregarded it, because I’d told myself full sheet was the only way to go.

Over time, I kept seeing him make very useful pieces with it, and my wall of fullsheet dogma began to erode. Bringing the wall down further was an experience I had with a local friend of mine, Brian Boatwright.

Brian (http://briankb.com/) is the biggest maker fan I know. He has lasers and CNC machines and 3D printers. He is always encouraging me to embrace this technology. My wife needed a sign engraved for a bench to honor a fallen Sheriff’s deputy, so I called on my buddy Brian because I knew if anyone could help, it was him. He said his CNC wasn’t long enough to engrave the full board in a single pass, but he could tile the pieces together.

Hold the bus—What? Yep, if the CNC is open on the ends, it is possible for it to handle pieces longer than the bed. This was a bit of a paradigm shift for me. Just because the bed measurements are only 36 inches long, doesn’t mean the machine was restricted to a 36-inch cut! Brian ended up doing a great job on the sign. I was captivated by the V-carved letters.

Locating an Affordable, High-Quality CNC

When I saw what my friend Charles Brazil, of First Coast Auto Creations, was able to do with his Shapeoko CNC, it helped push me toward acquiring my own machine.

Charles was posting photos of the work he’d been doing with the CNC, and that prompted me to ask him questions about his machine. He was using the Shapeoko by Carbide 3D. I did some research on the Shapeoko, and learned it’s very affordable (about $1,800 for the XXL model). It also had good reviews. Another appealing factor is that it had a big online presence. There were a number of Facebook groups supporting it, as well as an active forum.

Carbide 3D not only makes the CNC kits, but it also makes its own controller software—Carbide Motion—along with a design program called Carbide Create. Both of those are free and can be downloaded by anyone. I chose to do that during my research on the CNC and found that Carbide Create was very intuitive and easy to use. I could design things in Illustrator, which I am well-versed in, and import the vector art into Carbide Create.

From there, it’s a matter of assigning tool paths to the various line paths. I felt much more confident in my abilities with this than I did with Fusion 360, because I could use what I’m already familiar with.

I began to rationalize that it would be a good idea to buy a smaller CNC and learn the ins and outs, in preparation for a fullsheet model. This plan could potentially save me from making the mistake of a larger financial commitment on something that I might not be able to use. It was mid-November when I decided I would make the purchase. I had begun to see people ask about a Carbide 3D Black Friday sale, and after some research, I learned they typically do have a sale during that time. Once the sale was announced, I would make my purchase.

The Black Friday sale offered a free touch probe with the purchase of a Shapeoko machine. I chose the Shapeoko XXL because it was the largest model, offering a cutting area of around 33 by 33 inches (andlonger if the piece is tiled). Along with the machine, I also purchased a handful of bits to get me started.

One of the first projects I tried was a simple six-by-nine adapter plate.

Finding the Best Way to Store a CNC Machine

My first major decision involved how I would store the CNC. Did I want to build a table for it in my wood room? Should it be mobile? I decided that rather than leave it in the woodshop all the time, I wanted the base to be mobile, so I could keep it out of a potentially dusty environment when it wasn’t being used.

To save time in building a table, I found a modular shop table kit from Rockler. This kit would allow me to create a 48- by 48-inch bench that was 32 inches high (a little higher with the casters), and give me the flexibility to roll it around.

The rolling cart makes a perfect home for the new Shapeoko XXL.

The brace was welded in the middle, but bolted to the cart, in case it ever needed to be removed.

Rivet nuts were added toward the center to provide a spot for leveling the center of the cart top.

An additional hole was added to shift the drag chain enough to clear the X limit switch.

I planned on topping the bench with a piece of ¾-inch MDF.

While doing some research on what other people were using for their benches, I found the Shapeoko XXL wasteboard has the potential to sag in the middle over time. To give me the flexibility to adjust for any future sagging, and to further support the center, I made an X brace for the top. I added four rivet nuts. Bolts would apply pressure from underneath and re-flatten the center if my top ever sags.

Assembling and Setting Up the Shapeoko XXL

With my table ready, I headed off to California to work at Simplicity in Sound. It was hard leaving, knowing any day the CNC would arrive and I would be thousands of miles away! As usual, the time flew by quickly, and I soon returned home. The Shapeoko was waiting for me. While I was gone, I reviewed the assembly instructions, so I had a pretty solid idea of what was required for the build.

If you consider buying one of these for your shop, understand that it’s not a turnkey device. It takes hours to assemble and a few more of final tweaking and adjustments to dial it in. I think I was much better off assembling it myself instead of buying one fully assembled. The process of building the machine acquaints you with the different parts, their names and how they interact.

Items arrived neatly packaged in one large box. Individual parts were well-organized, separately boxed and labeled.

Assembly was straightforward. First, I had to make a modification to the bracket for the X-axis limit switch. If installed in the manner instructed, the switch would contact the wiring drag chain. I simply added an additional mounting hole to the existing bracket to allow the bracket to shift about ¼-inch.

Since the wiring drag chain is usermounted with no set location, shifting it slightly for clearance is no issue at all. Carbide 3D’s solution for mounting the plastic drag chain to the aluminum rail is to use VHB tape. While VHB is a great solution for some things, this is not one of them.

The spots of the drag chain mounting were drilled and tapped.

Bolting the drag chain to the rail made it much more secure than using the supplied tape.

The dial indicator made it easy to see where the adjustments were needed.

Charles suggested I use his method, and drill and tap mounting holes for the chain. I ended up drilling and tapping holes for not only the wiring drag chain, but also the wire tie mounting squares. They were also supposed to be secured with adhesive tape, but I knew in the Florida heat and humidity that it wouldn’t hold up.

Sometimes, I think, the instructions made a bigger deal about construction than necessary. It mentioned supporting the gantry on boxes when loading the Y-axis assembly; this seemed like something a normal person could do by hand. I didn’t feel like any part of the assembly was confusing or complicated.

A couple of spots in the instructions skipped over relevant steps, but if you understand the end goal, they are very logical and easy to figure out. Having the table already put together and ready for the machine was nice because I was able to build it and not have to move it.

One of the last steps in the installation is the wiring. I chose to deviate from some of their cable management suggestions in order to route the wiring a little more neatly. There is nothing wrong with the method they recommend; just know it can be done in a more organized fashion.

Completing the CNC Machine Setup

With the CNC assembled, it was time to move to the process of squaring up the bed and tramming the spindle. The instructions from Carbide 3D cover this process, but I found a more comprehensive explanation on YouTube on Winston Moy’s channel. I had been trying to square my bed, but I had somewhat of a parallelogram. All my efforts of loosening the end plates and adjusting didn’t seem to work. Winston suggested in his video using a ratchet strap to help coax the bed into squareness. I tried it, and it worked! I have also seen instances in which rails were not cut 100 percent precisely, so make sure to check your rail length as a culprit for squaring issues.

Once I had the bed square, I moved on to checking the squareness of the X- and Y-axis to the wasteboard. I purchased an inexpensive dial indicator that came with an adjustable magnetic base, and attached the base to the Z-axis spindle frame with the magnet.

Once adjusted, I slid the Z-axis assembly along the length of the X and Y rails and noted the measurements at each end. I was about .009 off on my X- and about .007 on my Y-axis. The X-axis required more work.

I removed bolts from the end plate and cleaned the powder coating off the plate openings to provide a little more adjustment.

With the holes slightly enlarged and some upward pressure applied to the low side, I re-tightened the fasteners. So far, I have found these tolerances to be more than accurate enough for the projects I have completed.

The final step in the machine assembly was to create a secondary wasteboard. Because most pieces will inevitably be cut deeper than their thickness, whatever is under the piece will be cut. It is common to preserve the factory board as long as possible by using a wasteboard on top of it.

When it comes to securing items to the wasteboard, I found the following methods often used:

• Simple template tape: This not only holds the piece securely, but also holds when pieces are cut loose from the larger substrate.

• Clamps: This seems to be what the majority use to secure their work. Two methods of clamp attachment are most popular: using T-track, and threaded inserts. A concern when using clamps is making sure the path of the tool does not run into a clamp.

• Screws: Yes, I have run across a few cavemen who just screw their pieces right into the wasteboard. This seems to be very barbaric because the screws will damage the wasteboard and throw off the flatness. I guess if the pieces you’re cutting aren’t too precise, then this might be okay.

I chose to use clamps as my method of securing, via T-track. I used six T-tracks that were recessed below the new wasteboard surface. The T-tracks I got did not have provisions for screws, so I had to drill and countersink the screw holes. The screws need to be flush in the bottom of the T-track so that bolts can slide in unencumbered.

Once the T-tracks were prepped and I had the wasteboard strips cut and the mounting holes sunk with a forstner bit, I clamped the pieces together onto the Shapeoko wasteboard. The bar clamps held all the pieces square while they were being screwed in.

This completed my secondary wasteboard and clamping system.

Next month, we’ll take a look at what I chose for dust collection, and some of the projects I tackled using my CNC.