Add zhop in Simplify3d? extruder sratching top layer surface

[swbluto]

I'm printing out a part and I've perfected the settings to create a perfect print everytime (I'm pretty impressed), but I noticed there's scratches on the top layer and looking at the "tool preview", it appears the extruder is traveling at that point where the scratch occurs. I set "retraction vertical lift" to 2.5mm and it seemed like caused the extruder to lift 2.5mm between different parts of the model, but the scratches are still there. I don't want to watch this thing print to figure out what's going on, but it seems like it's not lifting at that particular travel path on the top layer at the surface, scratching it while traveling.

I tried posting to the simplify3d forum but, dagnabbit, their reputation for hiding posts precedes them.

[jsc]

In the advanced tab, I think, there are options that affect when retraction takes place. Turn OFF only retract when traveling over gaps (I forget exactly what it's called).

[swbluto]

So, un-check the box called "Only retract when crossing open spaces"? Thanks, I'll try it out and let everyone know how it goes.

[Jules]

If the extruder is hitting the previous layer, you might have the Z-stop set just a little too close to the nozzle for the first layer. (I'm assuming that you have run the calibrations to make sure that the extruded widths are correct?) Now you just need to make a small adjustment for the height of that first layer, based on where your Z-stop is set.

You can easily make those adjustments in S3D based on the size of the calibration square that you print following Jin's write-up here:

viewtopic.php?f=3&t=1964

In the G-Code section of the printing parameters in S3D, there is a Z-Offset slot. After you print the first calibration square, measure the height with calipers, subtract it from 2.0mm and then enter that resultant number into the Z-Offset slot for that spool. (If the square is not tall enough, you'd enter a positive number, if it's too tall, you'd add a negative adjustment.) A positive number moves the bed farther away from the starting point for the first layer, so that the thread gets laid down evenly instead of getting squished out.

I run a second and maybe third square, just to fine-tune it, until I get a square exactly 2.0 mm tall. (Or within the tolerances of my extremely squidgy calipers.) I've discovered that i usually have to back off the initial adjusment by -.03....don't know why, I just do.

After that, i calibrate for the extrusion width according to the steps outlined in Jin's post using Ed's instructions. Gives as good a result as possible.

[Dale Reed]

Extruder dragging on the top of the part is also indicative of the part curling at the edges or pulling up from the bed. If PLA, be sure your bed cooling fan is running full out all the time. And run a big flat part (a large thinwall box is fine) and see if the corners or sides are pulling up off the bed as the part goes along. (You'll see it clearly on the bottom of the part after you take it off the bed upon completion.)

[swbluto]

So, un-check the box called "Only retract when crossing open spaces"? Thanks, I'll try it out and let everyone know how it goes.

Just letting everyone know, this did the trick! Stopped the scratching on the top layer's surface with vertical lift retraction set to .5mm! Thanks!

[Alloy]

I am having this same problem. I just ran the extruder calibration from the how-to thread with the 20x20x2 square. At factory settings I was print .25mm width and 1.70mm height. My extrusion multiplier is now set at 1.3 and z offset +.15; these settings give me a perfect calibration print.

I have tried to change the settings in the advanced tab with no success. Swbluto says he was able to solve this by unchecking "Only retract when crossing open spaces"...I have tried this and observed that the filament retracts but the bed does not. Is it correct the this "retract" is talking about the extruder drive and not the bed?

[Matt_Sharkey]

I am having this same problem. I just ran the extruder calibration from the how-to thread with the 20x20x2 square. At factory settings I was print .25mm width and 1.70mm height. My extrusion multiplier is now set at 1.3 and z offset +.15; these settings give me a perfect calibration print.

1.3?? Holy multiplier, Batman!

check your extrusion widths that they are set to what you expect? if you have the 0.35mm nozzle, then your extrusion width should be between 0.40-0.50

multipliers for common setups are between 0.90-1.10

[jimc]

Yes if your multiplier is that high then you dont have the filament dia set correctly. Retract when crossing open spaces should always be unchecked. In ooze control setting set retraction vertical lift to .2mm. Every time the nozzle move the bed should drop slightly.

[Alloy]

I am having this same problem. I just ran the extruder calibration from the how-to thread with the 20x20x2 square. At factory settings I was print .25mm width and 1.70mm height. My extrusion multiplier is now set at 1.3 and z offset +.15; these settings give me a perfect calibration print.

1.3?? Holy multiplier, Batman!

check your extrusion widths that they are set to what you expect? if you have the 0.35mm nozzle, then your extrusion width should be between 0.40-0.50

multipliers for common setups are between 0.90-1.10

New thread, viewtopic.php?f=7&t=2574, as to not go too far off topic on this one.