printing mirror image

I have built a corexy printer with home position in the bottom left corner of the print bed. all movement is correct as far as x+ toward the back, y+ to the right and z+ down. but printing is a mirror image of what is sliced . any help would be appreciated.

What does bottom left corner mean exactly? When the Z axis is at the bottom? Left front or left back?

Z=0 when the nozzle is touching the bed, not when the bed is all the way at the bottom of the Z axis.

If your prints are coming out mirrored, you have set up a left-hand rule coordinate system. It needs to be right hand rule coordinates. See: [drmrehorst.blogspot.com] and [drmrehorst.blogspot.com]

Edited 2 time(s). Last edit at 03/06/2019 02:03PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

X = L + R(Y = F + B ) though it doesnt have to be.

Edited 1 time(s). Last edit at 03/06/2019 01:50PM by MechaBits.

Sorry for the confusion Home position is X left front of bed Y is left side of bed (looking from top of the bed0

Front and back, left and right are tricky to use.

When you are speaking of a car, for example, you say these things as from the driver's or passenger's perspective, facing the normal direction of travel, front is then the part of the car that is towards the normal direction of travel, and left is 90 degrees counter-clockwise from that.

In the case of a 3D printer, we often want to use the perspective of the person who is standing in front of the printer, but for whatever reason, we define front as the edge that is closest to us, as if we were looking at our "car" in a mirror.

Generally, the X axis is defined as parallel to the front, going from it's minimum value, closest to the observer's left side to its maximum value, closest to the observer's right hand size. The Y axis is defined as perpendicular, going from its minimum value closest to the observer to its maximum value, furthest from the observer.

If you swap the X and Y coodinates, even with the home position in the same place, you will mirror image the resulting print.

Edited 1 time(s). Last edit at 03/06/2019 03:23PM by SupraGuy.

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

The conventional way to set up a CoreXY is to have +X to the right and +Y to the back. So you could swap your X and Y axes to achieve this.

Another way to achieve a right hand coordinate system would be to reverse your X axis so that +X is towards the front.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].