Replacing the Z axis bearings on my 3018 CNC

Recently I’ve started to hear a grinding noise when the Z axis was moving on my 3018. Clearly, this is supposed to be a smooth process, so I knew something was wrong. Before I started my next project, I better replace the bearings.

Fortunately, the bearings are a relatively inexpensive part on Amazon:

Amazon.com: uxcell LM8SUU Linear Ball Bearings 8mm Bore 15mm OD 17mm Length for CNC Machine 3D Printer 4pcs : Industrial & Scientific

The process for replacing them is involved though with total disassembly of the left side of the CNC machine. Fortunately, there is a video that walks through the process:

Doing a simple repair/upgrade on my Genmitsu CNC router 3018-Pro: slipping bearings

The individual that made this video also went through a modification process to keep the bearings from slipping. Rather than do that, I 3D printed some bearing clips that hold the bearings in place effectively:

CNC 3018 Pro bearing holders by cebess – Thingiverse

These clips are for the X and Z axis bearings, which want to slip out.

Never say never, again

Once again I noticed that I have not been blogging as much as I could/should.

I had dinner last night with a neighbor who is writing a book on architecture via many posts in his blog. This technique allows him to get down in the ether his thoughts, before he losses them. He can then mine that repository for more cohesive thought later.

The whole discussion made me feel guilty (don’t ask me why), since I have a number of posts to share that have been going on. I have been getting a number of weekly posts out for our local ham radio group, so maybe that has been quenching the posting desire. Oh well, here goes…

A while back I mentioned that I had done my last wooden tessellation. As in the case of so many final pronouncements, it appears that there was at least one more in the back of my mind that was waiting to get out. Since I had done shore birds, reptiles, sea horses, turtles… it seemed that fish were under represented.

This is my attempt to address that gap:

A fish based tessellation

That design is made from purple heart, walnut and hard maple using a design I created for my CNC machine.

Now, I just need to clean it up a bit more and then mount them all in a matrix of my office.

The last tessellation

Since I purchased by CNC machine, I’ve been creating various wooden tessellations. Now I’ve finished my fourth one and I hope my last.

It is not that these are that hard to design and create, it is just tedious.

I cut these out four at a time

I am thinking about taking all four designs:

Seahorse

Lizard

Turtle

as well as a topographical map of Hilton Head and the surrounding area.

I definitely know much more about the use of epoxy resins than I did when I started. It is hard to believe the lizard started back in 2019.

A trial at moving away from Universal G-code Sender for my CNC

It has been a while since I’ve written a blog post so I thought this topic was worthy. I was having trouble with the latest updates to GCS. The commands were just not flowing at a consistent rate. I rebuilt by old Pi2 and it still wasn’t working well. In the process, I had to recall all the things I’d forgotten about rebuilding the code and using VNC to access it.

Finally, I just thought to myself “What else is out there that may work more reliably?” I first built a version of Grbl Controller. This worked, but it was a pretty low end tool. I got the instructions to build it at:

Installing GRBL Controller on the Raspberry PI (alldonemyself.blogspot.com)

I then thought I’d try another open source approach. This one is primarily written in python. bCNC is a fully cross-platform solution. It was easy to install on the Raspberry Pi and runs within the GUI. This project is nearly full-featured with a g-code visualizer, code editor, virtual pendant, jogging, and easy coordinate system setup. I have it running over VNC still, though it wants a larger screen than my old 7” Android tablet I have mounted over my CNC machine.

Once you have python installed on the Pi, installing bCNC consists of:

sudo pip install --upgrade bCNC

You can also do an install from git:

sudo pip install --upgrade git+https://github.com/vlachoudis/bCNC  # if you want git version

To run it just:

python -m bCNC

The one problem I have had so far with bCNC is the visualization of the model isn’t quite right. It stops at line 9999, though the instructions to the CNC go all the way until the end. I am going to install from Github and see if that is more up-to-date. Here is what it looks like:

As you may notice (at the bottom of the screen) this G-code file has 456978 lines, so 9999 is just not going to cut it.

A process for creating Topographical Designs in wood using Fusion 360 and your CNC

A while back I wrote about a project I had done to create a map using my CNC machine. The Technology Special Interest group in our woodshop asked me if I could put together a high level presentation about the technique used. For the map I used information about the area around Hilton Head, SC. The rest of this post is a copy of those slides:

A high level summary of the process

There are numerous mapping resources out on the Internet. I found Snazzymaps as of the most versatile tools for creating designs that can be used with minimal manual effort.

Finding a map for your design

There are also many options for raster to vector conversions. Inkscape is the best open source alternative I could find. It may take you a bit of practice to understand the user interface… but there are many examples available.

Converting the raster data into something the CAD system can understand

Loading the correctly formatted SVG file into Fusion 360 is one of the easiest steps in the whole process.

Loading the map data into Fusion 360

In this example I used a 2mm flat bit for the contour cutting and a 60° V-bit to engrave the edges.

Creating the machining data for the CNC

Cut the design

Putting a finish on the design

In this post only the basics were covered. The possibilities are nearly endless.

Other options and designs

Finishing the cartography experiment

Way back in March, I wrote a post about an experiment in cartography using my CNC machine.

I never did get around to finishing it, until now. I happened to be in Hobby Lobby the other day and they had all their wooden craft boxes on sale. I picked one up for about $3 and then cut my wooden map down to fit inside of it.

I whitewashed the box and then epoxied the map to the bottom. There were a few bubbles that kept coming up off the map, so I swirled those into a cloud effect and then put a final coat of epoxy over the top. This is the result:

It is not perfect, but as an experiment I thought it came out fine.

An example process definition for cutting a 2D design Fusion 360

Recently someone in my neighborhood asked if I could cut the South Carolina logo in a cutting board he was working on. The board was already cut out in the shape of the state, so it seemed fairly straightforward. There were a number of steps involved so I thought I’d describe them at a high-level in a post just in case it helps someone else out. If you know of a better way, please let me know:

• 1. Find the design to cut and clean it up into an image file.

South Carolina logo

• 2. Use InkScape to covert the image file into an SVG file that the CAD system can work with.
• 3. Open a new design in Fusion 360
• 4. Enter design mode
  • Insert a canvas image of the cutting board that has been scaled accurately (I had a photo he’d taken)
  • Create a sketch and insert the SVG file that was created earlier (insure that it is scaled and positioned properly.

Design with the photo and sketch scaled and oriented correctly

• 5. Enter manufacturing mode within Fusion 360
  • Create the setup up based on the sketch model. Make sure that the zero point of the setup is where you want it to be. I made it 3mm deep since that was as far down into the wood I was going to cut.
  • Since this design has two parts, define an 2D Adaptive clearing for the gorget and the tree using a 2mm bit (since this design was fairly large, this size seemed sufficient.
    • For the adaptive clearing I set the stock to leave as half a millimeter but 1mm (half the bit width) should have been sufficient.
    • I also set the maximum roughing stepdown at 1mm (since my CNC machine is not all that powerful)

• I next defined a contour cut to clean up the edges. One thing you need to be aware of is if your cuts are defined on the inside or outside of the design. In my case, I needed the contour cuts to be on the inside.

• Finally, I simulated the entire process to ensure it was working the way I thought it would.

If I wanted to have more detail at the end, I would have used a 1mm bit for the contour cut.

Lost the motherboard on my CNC machine

I was performing a long running job cutting out a topographical map of the St. Pete area of Florida (for my son). Partway through the process, I saw a small puff of smoke and a heat sink popped off the back of my CNC 3018 Pro CNC machine. Anytime you let the smoke out of an electrical component — it’s not a good day.

If you were not aware, smoke is the thing that makes electronic and electrical circuits work. Don’t be fooled by scientists and engineers talking about electromagnetic force and electrical potential… All components perform there function based on their ability to store and manipulate smoke.

Just kidding…

I turned the CNC machine off and replaced the heat sink. When I turned the CNC back on, the heat sink popped off again – immediately. I figured at that point the motherboard was shot, so I looked for a replacement motherboard and found one on Amazon. I can investigate fixing the old one later but with surface mount components, it is probably not worth it.

New motherboard

The new component has a built in fan and seemed to have solid reviews, so I bought one. It came in a few days and only took a few moments to install.

Motherboard mounted

My CNC machine is happily cutting away again. I didn’t have to make any changes to my software…

Fusion 360 for woodworkers – session 1

During this social distancing opportunity, I’ve not been posting much lately. One of the reasons was I’ve been working on a getting started set of sessions for using Fusion 360. This is the tool I’ve been using for most of my CNC work.

This CAD package has many capabilities and a free hobbyist license. Since SketchUp moved away from a hobbyist desktop version to a web-based approach, moving to a more powerful tool seemed to be a wise thing to do. I can only hope that Fusion 360 doesn’t follow a similar route…

There are MANY Fusion 360 videos out on YouTube and numerous web sites covering the topic as well. Since I was putting together a series of sessions for our woodshop on Fusion 360 using a synchronous collaboration (Zoom), I thought I share the support presentation materials here as well.

There will be a post summarizing each sessions with a link to a PDF covering the material. As of now, there will be 9 sessions in all. Each one will have a bit of homework to cover before the next session. The goal is for the woodworkers to have a working knowledge of Fusion, not to turn them into a designer – I’ll leave that as an exercise for the student. A power and issue with Fusion is there are so many ways to do something.  I don’t claim that the examples included are the best possible, but hope they prove to be a useful example (even a bad example is still an example).

The session outline is (by session #):

1. An overview of the user interface
2. Creating a sketch with a line and a shape, as well as an introduction to parameters and constraints
3. Bodies and components
4. Fusion tips and copying design elements
5. Creating a lap joint and using parametric design
6. Parametric driven table base design
7. Mortis and Tenon, putting top on the table
8. Dovetails and using Revolve to create a pawn
9. Generating drawings

As I get feedback, I try to update the slides, as well as provide additional Screencasts, if the updates will enhance the understanding. This updating effort will hopefully make this a training resource for our shop, so I don’t have to give the class synchronously again and can just response to questions…

The first session PDF can be found here.

A new engraving project – Hufflepuff

Now that the 3D printer is operational again, I needed something else to tackle. So I dusted off the CNC machine — literally.

My daughter is into Harry Potter and has taken the test to determine she is a Hufflepuff. I had sitting around so I thought I would cut out the Hufflepuff crest. Here is what the crest is supposed to look like:

Hufflepuff crest

I only had Poplar available, so ended up creating this:

6″ wooden Hufflepuff crest

Poplar has long fibers and is not all that hard of a wood, so it did not come out as nice as I would have liked. This piece has no real sanding to clean up the edges, but that is easily addressed.

I used a 1mm flat bit to clear away the open areas to a depth of 2mm and a 60 degree V bit for the edges and detail. Overall, I deem the design a success. The next problem is determining how to finish it or to start over with some Maple or other more appropriate wood.