After assembling the AR4 the first time i wanted to have also the 7th axis being added. And i had a couple of things in mind which i wanted to modify. Please let me share my ideas with you:
the "huge" external box for the electric with all the corresponding cable towards the robot (in the current version of the AR4-MK3 this already improved - great)
the 2 cable strips from the joint1 to the electric box
POC for easy transportation, e.g. for demonstration, trainings, etc.
The "huge" external box is now screwed on the 7th axis plate and contains the 6 stepper drivers, the teensy4.1 and the arduino uno. On top i mounted the solenoid valve for the air gripper. The stepper driver for the 7 axis is located in connection box of the base plate.
https://anninrobotics.com/wp-content/uploads/2025/07/AR4-with-7th-Axis-and-easy-transportation-.avif
And the power supply can be placed horizontal or vertical
2. For the 2 cable strips i thought it might be a good idea to drill a 15 mm diameter hole into the J1 spindleÂ
and lead the cables on the bottom of the J7 travel track plate into the switch cabinet. To reduce the amount of cable running through the whole they are merged on top of the J1 spindle.
3. For easy and secure transportation i made a transportation lock which can be screwed onto the base plate and vice versa the joint 5 is locked onto this.
For grabbing now the whole plate a handle recess is milled out on each side.
Not for transportation, but for locking the whole base plate on my cnc machine some eight 8mm holes with 100 mm distance are drilled into this base.
Happy roboting 😎
This is really cool! Any video of this in action?
Hi Jann,
the cable chain is purchased, some IGUS 045.20.028.0Â (48pc = 624mm) and 0450.20.12PZÂ
(Connection element set), the motor and driver are as Chris suggested in his guide (
STEPPERONLINE Schrittmotor Nema 17 Stepper Motor 59Ncm 2A 1.8deg 2 Phase and driver DM320T) - i choose the open loop as for the moment i use the robot for learning and testing - on my cnc i use closed loop which saved me much more money than it costs (and also on my 3d printer i switched to closed loop-MKS SERVO42C kit). To be honest i didn't tested the limits of the 7th axis by now - let me check... 😉
Hi Jann, addition this how 7th axis it looks/sounds/work with Speed100 Acceleration 70 Deceleartion 70 hope it helps for your decision
Thanks, super much appreciated. You're right, the price difference is big and changing the motor for the linear track later on is easy (compared to changing say a motor of the arm). Your build look very neat and professional, hopefully I'll manage to pull off something similar. 😀 Now learning to work with ros 2 and build some c++ for control.
