Zaxis endstops

End-stops for the Z axis

Whenever you label a design with something like "Universal"  Endstop Bracket your asking to be taught that nothing is "Universal". Such was the case with designing Z axis end stops for my OX.
I needed a micro-switch on the top and the bottom of the Z axis's travel. There was no place to mount the simple "universal" brackets up in that very busy Z axis mechanism.

Since these brackets were essentially made on the fly, lots of trial and error, I do not have drawings for them. The parts were made from both .093 and .22 acrylic and bent on a shop made hot wire bender. Oh, and a dab of superglue here and there.

Down End-stop

The down end-stop is mounted on the upper Z channel top plate just below the Z stepper. I wanted to mount it on a stationary part of the mechanism and let the switch be activated by the moving axis. That approach eliminates wires having to move but there was no room. So I ended up moving the switch and as a result this switches wiring will have to be routed in a moving loop like the stepper.
The down end-stop interposes the lower roller plates as it moves down.


 
The down bracket. The switch mounts have slots for fine adjusting the stop position.

Mount of the down switch bracket. There is a clearance hole for the stepper spacer but it helps to keep the bracket from rotating. The left 2x holes are for cable ties.

Switch mounted and adjusted by moving up and down in its mounting slots. Interposes the lower roller plates.

Up End-stop

The up end-stop was much more complex to imagine and make but it is mounted on a stationary part of the assembly so the wiring does not move with the Z axis.
I tried something new in acrylic bending. Note the mounting arm for the switch is a feature of a one-piece bracket. The arm was formed on the hot wire bender :).

Single piece micro-switch bracket. The switches mounting is fixed but the bracket can be moved up-down (slot) for adjustment.
Bracket mounted on stationary side of axis. Cantilevered across to sense position of upper plate.

Showing both end-stops. Up on the left and down on the right

Up end-stop switch integrated (CA) with the breakout and spindle driver package

A complicated hack! Could use a simplification redesign.

Enjoy and comment,
Don



Comments

Post a Comment

Popular posts from this blog

A Simpler Spoil Board?

Image
SPOIL BOARD Google'ing shows that there are a gaggle of spoil board configurations out there. Since my initial build I have been using a spoil board made of particle board with routed T-slots. I used a secondary T-slot board to increase the holding options. This spoil board was made from two sheets of particle board with milled T-slots. The two board were joined in the middle using a lap joint cut on my router. This was material that I had yanked from someones pile of kitchen refinishing remnants. The upper spoil board was also made from particle board with T-slots milled transversely. Practical Work Holding I mostly have been working routing wood and that has driven me to use a different work holding method. The following approach will not work for milling metals at least not anything robust. Tape as a Work Holding Medium After many frustrations hitting the clamps used in traditional work holding ) using a variety or T-clamps) I investigated using tape as a hold
Read more

OX 48V spindle control

Image
Background DRAFT WORK IN PROGRESS One of the first steps in setting up the OX for operation is to calibrate the spindle speed vs the "M3" values sent from the TinyG. My first set of tests revealed a non-linearity in this control function. https://plus.google.com/+DonKleinschnitz/posts/AG6gZ7Lxhs7 This caused me to start a search to find, explain and remove the spindle vs speed linearity, the subject of this post. Donate: Please consider donating (button to the left bottom of this post). Your donations help fund additional research, tools and parts that I will return to the community as DIY information. Circuit tracing The Rio Rand controller was dissembled and a schematic was created. Theory of operation The key elements of the controller's design are: PWM input source choices: external or internal generated PWM selected by jumper External PWM: an opto-coupler interfaces the external PWM to the 555 which in this mode is used as a pre-st
Read more

DOX Power & Controller Module

Image
Electronics Packaging I had the following goals for the DOX electronics packaging: Modular, easy to wire, troubleshoot and repair Minimize length of power wiring Visibility of the controller lights Easy access to the USB plug Fuse protection EStop provisions Easy to access screw terminals on TinyG Provision for cooling Materials & parts: Base plates: .22 acrylic from Home Depot EStop frame: .22 acrylic from Home Depot Cover: .093 acrylic from Home Depot Black standoffs: 3/4x 3/4 acrylic standoffs. Scraps from pen turning Power Supplys: came with OX kit. Controller: TinyG Wire: various mostly from strippin old power cords EStop Switch:  Red Mushroom Cap 1NO 1NC DPST Emergency Stop Push Button Switch AC 660V 10A Terminal strip: 600V 15A 6 Position Double Row Screw Terminal Strip  AC input plug:  AC 250V 10A IEC 320 C14 Panel Mount Plug Adapter Power Connector Socket Inline blade fuse holders: Wallmart auto dept Special Tools: Shop built acrylic ben
Read more