Walls Breaking

Maybe the problem is the actual design. Try making it so the over hang is part of the wall bay making the wall the tickness of the overhang and the remove the area below the overhang instead of the wall and overhang being seperate parts.

After the 2nd print , it did come to mind, reinforcing the wall.

But, what bothers me, is that the wall itself is not easy to crack.
It could bend about 20 deg or so in half, before it breaks at a layer.
Also, printed only the 2mm wall. No prob.
So, I dont think its a temperature prob.  or maybe...?

ABS -255  PLA 230
Going to ck hotend temp w/ thermocouple thermometer.
Using an ole Simpson 388 analog.

Also, may try re-orienting on the bed 90 deg or 45 ? Maybe, its the slicer.
dunno.

"Your slicer is probably seeing it as two parts just touching rather than one piece"

Sounds logical. On the inside of the wall, where the transition starts(breaks), has this faint line.

In the modeling prog, I make sure that the extruded piece is merged.

But not following.
Poor design for 3d printing, or just a poor design ?

How many perimeter walls are you using? I would never use less than three for anything that needed to be structural.

I currently don't print abs over 230
what thermistor table are you using. it should be table 5

You should definitely fix that, you should be able to print ABS as low as 230c on an E3D, if not lower.

BUT, even if you do fix this, it will not solve your problem. As others have pointed out, this is entirely an issue with your design. FYI, even if you were injection molding this thing, it would still be incredibly flimsy and break easily, because the design is not suitable for plastic.

You only have a few ways you can resolve this.

1) Use ribs, as IronMan suggested
2) Fillet the walls on the inside or the outside. It doesn't matter which you choose, it's entirely dependent on your application.
3) Print the parts as separate pieces and acetone them together or bolt them together. Acetone will create a chemical bond between the two parts that is much stronger than a printed part by itself. Bolts will do the same. Acetone is the ideal glue for ABS, there's no need to use any other material for bonding ABS together.

This isn't a problem with your machine. You're simply not designing for the materials you intend to use. In general, with printed plastics, you should avoid sharp 90 degree angles where there are thin walls and/or no internal material. Additionally you should avoid harsh 90 degree angles between the XY plane and Z. When I was first starting out I found it very useful to observe how plastic things around the house were designed. One thing you will notice almost universally is that there are no harsh angles in most plastic products. They're simply too easy to break.

Here is a guide I found useful when I was first learning to design for 3D printing:
https://www.stratasysdirect.com/resourc … -modeling/

Did some wall test prints.
Model - .093"x 3" x2"

Extrude temp 255c - 40mm/s speed- .3 layer-.8 shell thickness- 50% infill- measured part thickness .093"
Hard to break
Extrude temp 260c - 40mm/s speed- .3 layer-.8 shell thickness- 50% infill- measured part thickness .094"
Harder to break
Extrude temp 255c - 40mm/s speed- .3 layer- 50% infill- 1.2 shell thickness- - measured part thickness .1010"
Can not break. Thickness out of spec. Oozing or too hot at ends.

Does this show it is using table 5 ?  Where is it defined ?
#define EXT0_TEMPSENSOR_TYPE 5

Probably no reason I should get involved unless I have an accurate way of reading the hot end.

yes that is correct...

I would try a print like yours but I am in the middle of a 10 hour .02mm layer 20mm cal cube to see if my machine can do it. Also I would probably make my model different as I would make a a cube that is 76mm by 50.8mm then take away from the inside to achieve the 2.4mm walls.

Honestly it is much easier to use the metric system since most gcode is written based on it in the first place and most printer software is made for it as well. I live in in Dallas Texas and personally do everything now in metric as it is so much easier to scale and manage prints.

Most of us here are used to using it and can relate to dimensions based on it better than imperial measurements. Just saying it would be easier for you.. Only reason I knew your measurements was I used my calipers that can switch between the two.

If you make a model by making a base then adding walls for the sides the slicer will see those as individual parts and may not slice the interface as structuraly solid as it could be. On wsy around this is to actually sink the walls into the base by a millimeter or more and then the slicer should see them as all one part and not make an interface or weak point between them. The other way is in your cad program is to start solid and remove what you dont need. Tinkercad calls it additive and subtractive modeling.