CNC Mod Pack

Description

There are cheap CNC machines sold in China such as the 3018, 2418, 1610 or LinkSprite Mini CNC. The unfortunate part is that is it cheap and you pay for what you get! All of the plastic parts that come with the machine are 3D printed.
The machine was so limited in its use so I set out to "repair" it by designing replacement parts and accessories. This would assist me in making PCBs at home with repeatable quality.

Details

The core of this project is the mounting bracket that allows anyone to create their own mounts.

The dimensions of the bracket are shown below so that anyone can use it as a starting point when designing their mounts.

The idea behind having a slot in the mounting bracket is to have all your tools at a known z-height. This probably does not get rid of the final z-height tuning but it will assist in the approximate height. For instance you should not have to adjust your laser again!

I have also made some parts that help protect the machine from the following common mistakes (my mistakes at least):

Crashing the bed and/or head into the frame by telling it to go beyond its limits
Crashing the tool into the bed by lowering it too much

To solve the above issues I made limit switch end stops. I had to change some settings on the GRBL controller which implements soft limits.

To install the limit switches:

3D print the X End Stop, Y End Stop and Z End Stop. I printed it all PETG and 0.2 mm layer height. This allowed a slight amount of flexibility to snap the end stops on the machine
Insert the limit switches (size is 13 mm x 6 mm L x W) into their respective end stop
Snap the z and x end stops into place. The y end stop requires one of the bolts and T type nut fasteners.
Follow the GRBL guide on wiring the limit switches. I have a woodpecker like board so I used those instructions. https://github.com/gnea/grbl/wiki/Wiring-Limit-Switches
Set up the homing cycles https://github.com/gnea/grbl/wiki/Set-up-the-Homing-Cycle
Do not forget to set the GRBL $130, $131 and $132 which specify how large your CNC work area is
Enable soft limits which stops the machine moving further than the work area. https://github.com/gnea/grbl/wiki/Grbl-v1.1-Configuration#20---soft-limits-boolean

To install the Z mounting bracket:

3D print the Z mounting bracket
Remove the original Z spindle/laser holder by first unscrewing the stepper motor. Then unscrew the lead screw from the spindle holder
Push the bearing rods out until you can remove the spindle holder.
Push the bearings and the brass thread out of the original z mount and put them into the new printed mount.
Reverse step 1 and 2 to install the new z mounting bracket.

Now you can install the laser or rotary tool by sliding it into the newly installed z-mount!

Designing custom mount:

If you need to make a mount for a different tool or a rotary tool then you should use the drawing below as a guide for the sizes. Don't forget to add tolerances!

Files

CNC X End Stop v7.stl

Print on its side

Standard Tesselated Geometry - 30.75 kB - 02/05/2018 at 05:01

Download

CNC Y End Stop v8.stl

Print as is - no supports

Standard Tesselated Geometry - 11.02 kB - 02/05/2018 at 05:01

Download

CNC Z End Stop v9.stl

Print as is - no supports

Standard Tesselated Geometry - 24.98 kB - 02/05/2018 at 05:01

Download

Tork Craft Attachment.stl

Print as is - no added supports

Standard Tesselated Geometry - 329.87 kB - 02/05/2018 at 04:59

Download

Tork Craft Top Mount.stl

This is best printed upside down - rotate it 180 in the x axes

Standard Tesselated Geometry - 66.59 kB - 02/05/2018 at 04:59

Download

Components

3 × Limit Switches About 13 x 6 mm (L x W)

3 × M6 x 30 nuts and bolts

1 × M3 bolt and T type fastening nut This is used for securing the Y axis end stop to the frame.

Project Logs

Collapse

Spring Engraver
Brandon Piner • 06/23/2018 at 07:56 • 9 comments

I want to be able to make really good looking PCBs at home. One of the missing elements is adding a solder mask.
Adding a solder mask from paint requires curing it with UV light. The trick is to black out the pads so that it is not exposed and therefore does not cure. I have not had much success with this method. But I saw a video (linked below - skip to 3:23) where an engraving tool was spring loaded to only apply a light pressure when engraving. This was then used to engrave away the solder mask where the pads should be exposed.
I have never been able to spring load my engraving bit so I decided to try and design a tool that allows engraving bits to be spring loaded. I decided to 3D print the part but it would be best if I could turn it on a lathe and mill.
This is the design I have come to test:
It is more clear from the cross section view. I am using the clamp from a terminal block to hold the engraving bit. I used a pen spring to push down on the terminal block clamp.
Go to 3:23 of the below video to see what the aim is
Source Files and Design Process
Brandon Piner • 02/20/2018 at 05:35 • 0 comments

As stated previously I used Fusion 360 to design the parts. I have linked all the designs below:
Rotary Tool Mount
X End Stop
Y End Stop
Z End Stop
The process I took to design the Rotary Tool mount was first to exactly copy the dimensions of the existing part. I used a digital caliper for this. Then I printed a couple versions until the dimensions were right.
Then I started to experiment with the mounting and really like the dovetail style slot with the bolt holes to secure it more.
After I printed the z mount I proceed to design the laser mount. I measured the dimensions of my laser and made a basic mount that can slide into the dovetail. Once I got the tolerances right I was happy to proceed with the next stage of the design.
The next stage was making the mount for the rotary tool. I knew I wanted the tool to screw into the mount as this would be the most secure. So I started by designing and printing a few screw threads until I got the best one. Then I added the dovetail mount and printed it. This version did not have a support for the top part of the rotary tool and this resulted in a large bending moment. I did suspect this would happen so I added in a z-stabaliser. This worked well.
Now that the machine was working well I did not want to destroy it! So it was time for the end stops. I measured the approximate distance between the two smooth rods on the x axis and tried to design something that would clip on to it. It took a couple prints but I got it right. Same process for the z mount. Since the same design was not going to work for the y axis I had to go back to the drawing board. I ended up using the limit switch in a different orientation but was still happy with the result. I had to design it to bolt on to the 2020 aluminium tubes. This was simple because I only needed to create a bolt hole for the mounting bolt.
Testing it on a PCB
Brandon Piner • 02/19/2018 at 07:33 • 0 comments
Rotary Tool (Dremel Like) Mount
Brandon Piner • 02/05/2018 at 04:55 • 0 comments

I have made a mount that will slot into the z-mount from previous logs. This mount is intended to hold a dremel-like tool - in this case it is the Tork Craft Rotary Tool.
The latest version STL files can be found here:

https://www.thingiverse.com/thing:2748598
I designed this in Autodesk Fusion 360. My first attempt was just to see if the concept would work so I did not print the whole mount. Just the bottom piece where the rotary tool slides into.
Once I did a couple trial runs with that and was happy with it, I added the top piece which stabalises the rotary tool from lateral moments.
Y End Stop Limit Switch
Brandon Piner • 01/26/2018 at 05:53 • 0 comments

I have designed the Y end stop slightly differently to the rest of them.
I have not done repeatibility tests on this limit switch but I am fairly confident that it will be fine.
Latest version can be found here https://www.thingiverse.com/thing:2767979
Added a video of it working
X End Stop Limit Switch
Brandon Piner • 01/26/2018 at 05:35 • 0 comments

Here is the X end stop that I have designed.
Find the latest designs here https://www.thingiverse.com/thing:2768190
Z End Stop Limit Switch
Brandon Piner • 01/25/2018 at 20:48 • 0 comments

The Z end stop is the first of the limit switches I am designing for this CNC.

It takes a fairly generic limit switch of about 11 x 6 x 7 mm (L x W x H)
The latest version can be found here https://www.thingiverse.com/thing:2765402
Z Mounting Panel
Brandon Piner • 01/25/2018 at 20:13 • 0 comments

Testing out the z mount with my laser diode

Uploading all Z Mounts to Thingiverse https://www.thingiverse.com/thing:2748598
Laser diode mount

Tork Craft (Dremel-like) Rotary Tool Mount

View all 8 project logs

Discussions

M Druiven wrote 03/21/2020 at 16:08

Question. What is the diameter of the tool holder strap on the Tork Craft Top Mount file? I am looking for something to hold the original DC motor spindle on an old 2418.

Are you sure? yes | no

ricky.peruzzi99 wrote 03/26/2019 at 12:11

Hi. I think that my cnc has the 0.9 GRBL version. Do I have to update it to use limit switches?

Are you sure? yes | no

M Druiven wrote 03/21/2020 at 16:05

Not from what I have seen. The original Woodpecker 2.6 has Zen and Yen and Xen inputs but I have not researched it very much yet.

Are you sure? yes | no

pbilke wrote 12/27/2018 at 22:55

The Design file marked X endstop is just another copy of the Tool mount.

Are you sure? yes | no

CNC Mod Pack

Description

Details