Printing Bed Advice

**[Document in Draft Edit]**

Correctly setting up your printing bed is an important step to having good quality prints.

### **Bed Levelling**

Bed levelling is very important for a good print quality. If the printing bed is poorly levelled, the first layer might not stick, be under extruded or the printing head might touch and scratch the bed.

Before you start bed levelling in Rotrics Studio, make sure that the DexArm itself is secured to the work surface. This can be just with masking tape across the corners of the base. Next, place the build plate in front of the DexArm and make sure its straight. Place some masking tape under two of the corners so you can put it in the same place each time after cleaning / removing parts.

Place Masking Tape Under Corners and mark the corner. [Illustration by Chris White]
For optimal prints, the bed needs to be as flat as possible. A 3D printing grade glass bed is a good choice because it's usually very flat and heat resistant. You can use the included glass bed, but the rubber pads on it don't guarantee the evenness of the printing surface. A 220 X 220mm 3D printing borosilicate glass bed is perfect and easily available online.

In addition to being flat, the bed must lay on a flat surface. You can use a spirit level to make sure of that. Remember, unlike a traditional 3D printer, the arm is completely separated for the bed, so it needs to rest on the same flat surface.

After finding a suitable printing bed and spot to rest it on, the software bed levelling procedure can be used to correct any remaining unevenness of the bed. This four points levelling procedure is far from optimal, it can correct some unevenness but a flat surface and a flat bed are a prerequisite to improving print quality.

Once your build plate is in the correct position,

#### **Current Bed Levelling**

The current bed levelling data can be found by entering the following command into the Rotrics Studio Terminal whilst connected to DexArm.

**M892**

To reset your DexArm levelling back to zero, enter the following at the terminal then disconnect all cables from the DexArm. Reconnect and power back up to continue.

**M891 X0 Y0**

You can then proceed to do the Rotrics Levelling Wizard to level the 4 fixed points. After this you can return to the Terminal and enter the following command again to reveal how far from zero your current setup is. You want these numbers to be as close to Zero as possible. Any deviation from zero implies a less than perfect printing surface. It is acceptable to have deviations of 0.05 or less to be ideal.

**M892**

#### **Bed Levelling System**

To make sure the bed is really flat, you can use a simple mechanical levelling system.

1. Take a wooden board slightly bigger than your glass bed, and drill 4 holes in the corners for (M5 for instance) countersunk screws.
2. Put the screw in the board. Add in that order : a washer, a nut, a wing nut (flat size facing away from the head of the screw), and a build plate support pad
3. Then place the build-plate on the support pads. You can add rubber pads, double sided tape or tacky gum to better maintain the build-plate on the plastic pads.
4. Finally adjust the wing nuts on the four corners of the system to level the build-plate. You can put the arm at a fixed Z coordinate and move it along X and Y while adjusting the nuts to see if it's distance to the build-plate is the same everywhere.

You can print the build-plate support pads using this 3D model and change the parameters in openSCAD to fit your screws.

### **Non-Heated Bed Preparation Techniques**

#### **Method 1 - Glue Stick On Glass**

* M1.1 - Prepare the Glass Bed by making sure its thoroughly clean. Use Soap and Water to ensure its free from debris and make sure its completely dry.

* M1.2 - Secure the glass bed to the marked positions you created during the levelling process as shown above. Tape the edges of the plate down with masking tape.

Ensure all edges are taped down firmly. [Illustration by Chris White]
* M1.3 - Just before you print (a good time is when the nozzle is heating up) - using a smooth Glue Stick (Elmer's Purple Glue Stick is recommended), smear a single even layer across the glass in one direction only. No overlaps. Ensure you have even coverage.

Apply Glue evenly in one direction. [Illustration by Chris White]

#### **Method 2 - Tape On Glass**

* M2.1 - Prepare the Glass Bed by making sure its thoroughly clean. Use Soap and Water to ensure its free from debris and make sure its completely dry.

* M2.2 - Position the glass bed on the marked positions you created during the levelling process as shown above.

* M2.3 - Apply rows of tape on the glass bed that extend onto your work surface. Make sure that each piece of tape is as close as possible to the last one, and that it also secures the glass bed to your work surface. The tape should not be overlapping, as a minor height difference like this can result in poor quality or even failed prints as the nozzle reacts to the height difference. You are now ready to print.

* M2.4 - Some people still wish to apply glue to this surface like step M1.3 above. This can be done but is not necessarily essential.

Apply rows of tape, not overlapping, and leaving as small a gap as possible. [Illustration by Chris White]