Machine-specific attachments

To make our machine hack more easily adaptable for any machine in any lab, we decided to split the tool holder development into two parts: the universal tool holder and the machine-specific attachment. This means that if you would like to use our machine hack in your lab, you only need to adapt the machine-specific attachment based on the dimensions of your machine. The universal tool holder connects to the machine-specific attachment with two bolts. The distance between these bolts is the same as on the Axidraw mounting plate. This means that universal tool holders can be attached directly to the Axidraw, without machine-specific attachment.

Shopbot Machine Attachment

In our pilot research we are focusing on the large format milling machine we have in our fablab: a Shopbot.

Fabricademy 2023/2024

Together with Fabricademy students, we developed the first Shopbot-specific attachments during Open Source Hardware week in November 2023. They all attach to the machine around the spindle with a simple tightening mechanism, which worked well.

We started out with some measurements:

The most important measurements for the Shopbot are the spindle and collet assembly. We move the skirt and the ventilation out of the way. We used an end mill in the collet to zero the Z axis of the machine. Maximum height has not been taken into account as we will not go near the maximum height of the Shopbot.

You can read more about the machine hack developed during Fabricademy 2023/2024 here.

Shopbot spindle attachment 1

After this kick-off, we continued with their research. We broke the design down into two parts: the universal tool holder – so tool holders that we are developing for use with other machines as well – and the machine-specific attachment. The first iteration clamps around the spindle and has a mounting plate similar to the AxiDraw.

Printed before assembly with the threaded inserts:

Attached to the Shopbot:

Shopbot spindle attachment 2

The first Shopbot machine attachment already works fine but it’s quite bulky, so we made another one that is lighter and quicker to print. In this iteration there is also space for a servo motor for the swinging tool holder. With the previous machine attachment extension screws were needed for this.

Here it can be seen with an alternative tool holder (clamping and rotating) attached to a prototype for a revolving tool holder (without the servo motor).

Shopbot spindle attachment 3

For the third iteration, we wanted to integrate controllable up and down functionality. This design includes a modified version of an existing linear actuator design for a micro servo motor found on Thingiverse.

You can see this version in the video here, where it’s being tested with DIY interactive sensors developed during Open Source Hardware week 2024/2025.

Fabricademy 2024/2025

In November 2024, we continued development of the Shopbot machine hack. However, we had to change the method of attachment to the machine, since we were no longer allowed to attach bulky things to the spindle. We opted for a velcro system around the entire Z axis assembly with the ink deposition system, and attached the tool holders to the mounting holes where we removed the dust extraction system. We destroyed the linear system above and attached it to the new machine attachment. This attachment is actually way simpler as it is just a mounting plate with two holes to attach to the Shopbot, and two holes to attach the tool holder.

AxiDraw

For the AxiDraw we do not need a machine attachment, since the tool holder will be adapted to the attachment plate for the stock pen holder. We will replace the stock pen holder but reuse the vertical mounting plate for our machine specific attachment. Here are the measurements of the AxiDraw mounting plate: