Z- Axis Designing & Changing the Orientation

Dear All Reprappers,

I have been trying hard to know the facts of designing a 3D printer.

I have few basic queries, rather I need to be clarified.

1) How the Z Axis movement is controlled via the Firmware, For Eg I have my Printer Connected to Threaded Rods and moving the whole X Plane in Upper direction for Increasing the height of the Printed Object.

I would need to make the following changes to my design, which is the best way to start and proceed.

a) I would need my Z axis movement to be controlledby making the X axis seperated and the Z axis moving from top to bottom, Sure I will need a mechanical design like replacing the threaded rods with Acme screw, how this can be effective with firmware and software knowing these mechnical changes.

Can anyone guide me through some documentation. I would love to design or modefy my existing printer and learn from it.

Regards

Pingnagan P

The Z axis stepper motors' step per mm setting in the firmware is all you need to worry about. Design the mechanism, then you'll be able to work out the new steps/mm based on the number of steps per revolution of your motors and the various ratios of whatever mechanism you come up with.

All that assumes a linear mathematical relationship between motor and axis motion, otherwise you'll be getting into writing some software or taking advantage of existing software for similar nonlinear mechanics.

Thanks dale, while this very generic, can I have some way to learn better in corresponding to PRUSA or other know models here, I know this room is full of experts in some or other way, Where would be the best start point to learn or have some documentation.

Thanks in advance.there is so plenty of info, equally anyone could get lost.

If you change the screws, you will need to a new Z steps per mm parameter and change it in the firmware. If you are changing the direction of motion, you will need to invert the motion in the firmware or reverse the wiring on the stepper motor. Both firmware settings are found in configuration.h if you are using Marlin firmware.

Download the Arduino development environment and spend some time getting to know what is in configuration.h to learn more about what can be adjusted there. Once you can do that, most of your questions will be answered.

thanks pal, i will certainly look that.

How does the Z axis works in the XY core mechanism, Im little concerned or would like to know how the height of the object is determined.

The CoreXY machines don't really have a particular Z axis arrangement associated with them. It really shouldn't have any requirements that are different from other Cartesian motion printers.

So how does this XY core mechanism understands the Z height, Im really new on designing these printers, If im blank, please bear with me.

XY will have the extruder movements associated simultaneously with both the direction, where the base plate remains constant- Does this not affect the speed of the printing.

Throw some light

Regards

PP

it's all in the name: coreXY. Z axis operation is not part of the design. Any z axis design will work and it doesn't effect the kinematics of the XY operation.

when the gcode tells the printer to move the z axis 0.1 mm, it turns the z motor x amount of steps to achieve a 0.1 mm movement. That "steps per mm" dimension is determined by you, the operator, through calibration. You do this my telling the printer to move the z axis 100 steps, and then measure how far it has moved, and then do the math to figure out how many steps are needed to move 1 mm.

So, the printer only "knows" what 1 mm is because you tell it what it is. if you get the calibration wrong, your printer isn't going to correct it for you.

Anyway, if you change your x and y axes to coreXY, and leave all the z axis parts the same (don't change the leadscrews or motors or gears or whatever) then your "Z steps per MM" number won't change (you'll probably still want to re-calibrate, though)

Edited 3 time(s). Last edit at 02/27/2014 11:47AM by Buback.

thanks a ton Buback,

All that Im wondering now, is should someone mention the mechanism as XY kinematics in firmware, so that it would improve the stability and the motion of the Axis.

If you are asking whether you have to define in your firmware what type of kinematic model to use, then yes, you have to define that. Marlin includes kinematic models for regular cartesian bots (simple XYZ), coreXY, and Delta. I've never had to change it, but i'm sure it's as simple as changing a variable.

https://github.com/ErikZalm/Marlin

Hello Buback,

Thanks a ton, let me go through the attached, a special thanks again, for immediate reply.

PP