In summer, I went to Woodcraft and grabbed a bunch of blocks of wood to make x-mas presents for some friends. I already had an idea of what I was going to make from a project video I saw on Inventables’s site. I wanted to make Passive Amplifiers that would double as a desk nameplate. Rather than use the pre-made file from Easel, I wanted to do my own in Fusion360 to get more practice.
Before I had any time to work on this at all, I ended up buying the new beefier gantry makerslide. I also 3D printed an enclosure for my smoothieboard and an enclosure for my E-stop button, both from thingiverse.
Literally at this point, I’ve got enough extra makerslide, plates, belts, ACME screw and nut set and gears to build a Shapeoko 2 (missing bolts, nuts, washers, V wheels, bearings, or idler wheels). Leave a comment if you are interested in purchasing my extra parts.
I also had beefed up my gantry motor to a NEMA 23.
Processing the Blocks:
Once I had made the changes to my machine (a never-ending project in itself) I got to work on the passive speakers. I clamped my handheld belt sander upside down in my workmate bench (I do not condone this stupid behavior). I sanded down all the blocks until you could no longer see the bandsaw marks using 150 grit sand paper. I rolled the edges and ends to get nice rounded edges. This worked for the most part, but sometimes I got inconsistent results along the entire edge of the block which looked bad and wasn’t easy to fix.
After rough sanding, I hand-sanded the corners to remove the sharp point using 150 paper by hand, then used 220 paper on my orbital sander to remove the traces of the rougher sanding and smoothed out the overall faces. Due to time constraints (I was so busy that I waited until the last minute to do these) I went ahead and hit the blocks with Tung Oil every other day for about a week. This soaks in and if I had done it more would really bring out the luster int he wood. It smells a bit funny so I left the blocks in the garage to air out. Tung oil is good because it won’t combust spontaneously like a lot of oil-based stains. Heck, the guy that sold it to me said he never even wears gloves and has been using it 20+years. I wore gloves anyway.
After the blocks were processed and thoroughly tunged, I went about using Fusion 360 to design the passive amplifier element. Unlike the inspiration project, I wanted a continuous spiral as my cone. I created a block approximately the size of these blocks, then I created a spring. It took a long time to figure out exactly how to get the spring to have the features and be be the size I wanted. I then had to merge this with a cone shape to create a single solid body that was a helical cone shape. I put it on the block and performed a difference operation to remove the helical cone shape from the block. Then I added the slot for the phone. I used my and Jess’s phones as tests using a block of scrap 2×4 to find a width that fit both of them.
I can’t say this was intuitive. When I ran simulations of the cut, I kept having weird errors that would break an endmill in the real world. For instance, the bit would circle the perimeter of the helical cone step by step, leaving a huge plug of wood in the middle 40mm high to be cut from the side at the very end of the job. In order to remove this weirdness, I had to get creative with the cuts. Firstly I used a plunge cut to cut the very center of the cone out in several passes. As you can see in the image at the top of this article, there’s a bit of an error at the right side near the top of the helical cone. This is due to the lead-in of the plunge cut. In later iterations, I removed that stupid lead-in. I have no clue why it would generate paths that would defile the user’s design, but it does…
Then I used a contour cut to remove material for the slot and helical cone in multiple passes. The Fusion 360 simulator said it’d take about 5 minutes for the whole shebang, but it took about 3 times longer in reality. I’m not sure how to reconcile this.
So I intentionally went against my best judgment on this one. Looking for a cheap engraving bit, I ended up at Harbor Freight. I found a pack of 5 HSS router bits that included an engraver for $8. Since an engraver bit is usually taking a bit more light duty use than other bits, this was a good deal. Other bits were like $25 just for the engraver elsewhere! My mistake happened when I considered using the half-inch router bit as an endmill. I figured if I take off only 1.5mm at a time, then it couldn’t hurt to use this router bit slightly out of its specified application. So I went ahead.
Surprisingly, this worked beautifully for the first four blocks I milled. The last one had ragged edges though. Since I needed to make about 4 more, I went back and bought another Hazard Fraught bit set. This was enough to cut the bulk of the gifts I was making. I had another 2 blocks to mill, but I had a couple weeks to finish those while these first 8 were needed literally that night at a party.
After I milled them, I had Jess get one of her fancy fonts and make some SVGs of our friend’s names to engrave on the other face of the block so it could be used as a nameplate on their desks. This was easy to do in fusion in a new file. I simply created a block the size of the wood I was using, then imported the SVG onto the face of the block. The Z axis here is still setup so the tool comes from the top (ie. as if the block has been rotated so that the face is pointing upward). Simply go into CAM and do an engrave and it’s done. The results came out beautifully!
The problems started when I moved my CNC machine the garage form the office to avoid the dust. I used one of those half-inch bits and aligned everything and let ‘er rip. I was making a video when the failure happened…
I hit the E-stop immediately but it still screwed up stuff. The bit came loose and slipped down as the router continued to spin (likely screwing up my quarter-inch collet) The CNC kept moving for a short time as well until I could hit the E-stop. This caused the bit itself to break. Luckily no chunks of it came loose or flew off at the 22,000RPM I was running at, but it came close as the pics below show.
After this error, I went ahead and redesigned the toolpaths to use a proper 0.25″ endmill and tried cutting another block. I didn’t get to see the final result, BUt I’m pretty sure the lead-in screwed me on the first plunge cuts I did. I didn’t finish the part because like a genius I stuck the vacuum cleaner hose in the way of the Z cart and ended usp causing my X axis motor to skip a bunch of steps as it wedged the vacuum hose into the block. I’ve yet to revisit this. even this short amount of exposure to the incredibly fine wood dust made my nose clog up again(even wearing a respirator). I had to go back to work after new years and haven’t had a chance to revisit (or document) and projects until now.
It has been bout a year now since I last had a chance to play with my CNC machine, so I figured I’d give an update on the progress so far and what I’ve learned.
Firstly, I got the Dewalt 611 router and router mount. This is a huge upgrade from the no-name dremel knock-off I had. After test cutting just once with the old router, the brushes were shot. I sprung for a real tool instead of a toy. As a bonus, it makes the machine look nicer as well. In order to fit 1/8″ shank bits, I had to get a 1/8″ collet for the DW611. This wasn’t terribly expensive if you compare the cost to replacing all of my router bits with 1/4″ bits. I got all of this late summer 2015 and literally had only enough time to attach it all to my machine before life got crazy busy. I never even had a chance to test it until now.
I also recently got the Suck-It from kickstarter. This goes a LONG way into keeping dust to a minimum. A warning, however, I tightened the screw too tightly on my Suck-it and accidentally drove the bottom edge into one of my makerslide rails since I don’t have endstop switches. This promptly shattered the Suck-it acrylic into incredibly sharp shards. While you can purchase additional parts from the Suck-it website, I opted to make my own replacements from wood, which is a bit more forgiving.This also gave me a great chance to finally learn some CAD software.
While testing, I finally realized that the ACME screw inventables sent me last year as part of my upgrade kit is warped. It binds in a couple of places when I try to move the Z-axis up all the way. I thought that I could fix this by simply getting a stronger motor, so I ordered the NEMA 17 from inventables. This was stronger, but still couldn’t overcome the bend in the screw. The bend also causes the very tip of my bits to wobble ever so slightly. It is almost imperceptible, but makes a big difference when I mill multiple passes of the same shape or try to do PCBs.I contacted Inventables and Mo in customer service worked with me over a couple of weeks to get my Z working great. It turns out that Since I upgraded from Shapeoko1—> Shapeoko2–> Xcarve, I had the wrong spacers on my router mount. The ones I had were about 2mm too short. Mo helped me get the right length spacers (9.5mm long) and bolts(35mm). My short spacers and bolts were causing the ACME screw to bend back towards the gantry at a significant angle. When installing the new spacers, be sure not to use washers as this will also change the angle of the ACME screw. With the new spacers installed I can get all but 7mm of my Z axis working perfectly smoothly. Thanks Mo!
I also bought this clear tube for my suck-it vacuum mount. This was about 63mm in diameter, so I had to same the interior of the acrylic suck-it plate to fit the tube. I also cut it to about 9 or 10 inches in length. At this height, the tube is about the height of the router itself. This gives me more visibility to see what is going on with the business end of my router rather than the black coupling tube that the suck-it came with.
I wanted to learn a real CAD package since my FabAcademy training in 2014. I only had experience with Sketchup which, while very good for beginners, it doesn’t really follow the same kind of workflow as professional engineering CAD/CAM packages. I wanted to learn something along those lines. I had played with Creo, Solidworks, Antimony, and was looking into Rhino/Grasshopper when I saw Fusion 360. Autodesk has been going crazy buying and building awesome CAD/CAM tools for the hobby market as well as for industry. Fusion 360 is a complete engineering tool that can start with a 2D sketch or a 3D body and allow a user to create objects, render them realistically, stress test them with finite state analysis, and export 3D print or CNC toolpaths. Oh, and did I mention that it is free and has a very active community online as well? So I downloaded it and gave it a try. I am quite pleased with it in all respects!
Having no formal training, I opted to take some free online courses from Udemy.com. Check out my other posts concerning that. Of course, as with anything, beginning is the toughest part. It took me a couple of days to get the hang of the Fusion 360 workflow, but with all the great tutorials and videos online, it is easy to find answers to your questions. If not, you can post to Autodesk’s forum for help.
Moving on, I played with Fusion 360 starting with the 3D sculpt method at first to get some awesome organic shapes, then moved to learning the 2D sketch workflow. I measured my machine and aluminum rails of the Suck-it. I made quite a few mistakes along the way, and had to start over several times, but I finally figured out how to get what I wanted out of the software. It is still a bit buggy from time to time and crashed a few times when I tried to do certain things, but I think it was partially due to a bad design. I watched a couple videos and fixed my design and was able to create the toolpaths without further issue.
Fusion 360 can do 2D and 3D milling jobs with ease. There are a lot of options, but videos mentioned in my previous post cover most of what you need to know. I’m running a smoothieBoard on my machine and Fusion 360 has a CAM processor script designed for my board, so I simply select “Smoothie” from the dropdown menu when I go to export my design and I’m good to go.
Sending the job to the machine:
The main software people are using to send jobs to the smoothieboard is Pronterface, which is typically used for 3D printing. It’s all Gcode, so it doesn’t really matter, but for some reason, I didn’t like using a 3D printing software for CNC. Last year I tried using Universal G-code Sender with the smoothie and even played with coding in this ability, but life got too busy for me to continue, so I stuck with using Pronterface. What I like about Pronterface is the ability to create custom buttons. For example, I made buttons to zero the axes, reset the smoothieBoard after I hit the killswitch, etc. These prevent me from having to manually type the Gcode in the command window. I can even send smoothie console commands using these buttons.
You can also run the smoothieboard over ethernet. You can do so through pronterface or by using one of several web interfaces (meaning you can control your 3dprinter or CNC machines over the web). This is useful in my FabLab at work where we have a lot of 3D printers running on a 3D print server. You can run the smoothieboard on this as well. It can host several different web interfaces which I hope to go into later, but one of them is basically a webpage that looks just like pronterface.
I feel like I finally have a good workflow here. You can see my results here. I made replacements of the broken acrylic pieces of my suck-it dust boot that I made in Fusion 360. I used scrap wood, so it had quite a few drill holes going all the way through it already. I also did conventional only, and no climb milling which would have given a nicer finish. I used a 2-flute straight 1/8″ but as well, no spiral which would have also given me a cleaner result. Due to my learning curve, I did have to do some manual touch ups to the dimensions of the pocket which explains the nastiness in there you see.
Many designers use some kind of computer-aided design or CAD software to make 2D and 3D designs. A common one used by many people is Rhino (especially when used in conjunction with the Grasshopper plugin). Fusion 360 is a newer, easy to use, free complete CAD/CAM package. If you are going to learn any CAD software for practically any purpose (designing, engineering, fabrication, rendering realistic models, etc) it should be Fusion 360.
Fusion 360 is an Autodesk application that can do many useful things for designers. Whether you want to do something as simple as making cool looking 3D models to stress testing (finite element analysis) and even simulating the simple physics of designs and even milling them out or 3D printing them, Fusion 360 has you covered. It can also render realistic materials and surfaces and make animations of your working mechanical devices. Did I mention that it is free and there are tons of free online video tutorials and classes showing you how to use it with example projects? Oh, and so you aren’t reinventing the wheel (or other simple hardware) you can bring in models directly from McMaster-Carr who carry all sorts of nuts, bolts, gears, chains, etc. which can save you loads of time. This is my brain dump for getting started with Fusion 360 and using it with my CNC machine and my wife’s 3D printer.
Download Fusion 360 for free license. They have yearly licenses for hobbyist and I think even small business, or you can get a 3 year license for education.
Learning to use CAD:
At this point, there are two methodologies to use when creating parts in Fusion 360. If you have CAD experience already, you might be more comfortable drawing 2D parts then extruding them into 3D, etc. If this is you, then check out this free training class. The second methodology is sculpting. It begins with simple 3D shapes you can manipulate almost as if it were made of clay. This is great for 3D smooth shapes. Check out this great free training class for this methodology after taking the first section of this class. These two methodologies don’t replace one another, rather they compliment each other. You will eventually need both for complex designs, but start with whichever one is easiest for you so you can progress quicker. I personally love the “sculpting” mode.
Since on a CNC machine, the Z axis is the one you attach the router to, you will need to change the position of the Z axis in Fusion 360. Then set your preferences such that Z axis is the top axis. Within Fusion 360, click your name at the top right->Preferences. In the main window that pops up, about half way down, there is a “Top Axis” option that is set to Y, change this to Z and then “Apply” Now Z is the top axis like on your CNC machine. This will work for all NEW documents, but if you happen to have an older design or are importing someone else’s design, there’s a couple different ways to change the Z axis. The simplest method is to select the up-axis when you “setup the job” in Fusion 360. This is done when you are finished with your model design, and want to start creating the toolpaths.
Now, get into making some stuff. While Fusion 360 can do 2D and 3D designs and generate toolpaths for the CNC machine, there are lots of simpler (dumber) 2D workflows out there that are great such as Makercam.com or Easel from Inventables, etc. I’d use Fusion for more complicated 2D and 3D designs. For example, Easel won’t allow you to use a chamfer bit or V bit for engraving last I checked, but Fusion 360 will. This can make some amazing 2D designs.
You will notice that some of the videos tell you to delete certain lines in the generated Gcode from Fusion. This is mostly because it adds a “home” command and many DIY CNC machines don’t have homing switches. This command might tell your machine to go to the maximum extent of your machines to find the switches, but since you have no switches, it’ll end up messing up something. So many of the tutorials suggest removing the G28 (home) line from the Gcode Fusion 360 generates. If you have a smoothieboard controller, you should be fine to leave it in as long as you have set up your config files correctly.
How to set your origin to a different are of the design for milling. The best setup is one like the Othermill uses which ensures you never cut into your spoilboard. “Don’t spoil the spoilboard” is a great explanation of this method. I hope to make vids on how to in fusion 360 and real machine.
Can export to Othermill, or Smoothieboard, pocket NC, or other mill. Tons of options in the “Post Processing” menu.
You can simulate the milling process. When you do, the paths have different colors. A post on Autodesk’s forum cleared up what they mean:
Here’s my video of an example project I made. It is full of tips on stumbling blocks I came across.