<p>The general recommendation for layer height is to go no thicker than 75% of the nozzle diameter. Your post states 0.4 mm layer height with a 0.4 nozzle, exceeding the recommendation.</p>

<p>If your first layer is dropped to 0.3 mm, you'll fall into the recommendation, but the thickness is a reference for ALL layers.</p>

CC BY-SA 4.0
2020-01-05T13:21:43.837Z
I'll try this out tomorrow. Hopefully, this is the answer.
Perry Webb
CC BY-SA 4.0
2020-01-05T12:14:30.437Z
2020-01-05T12:14:30.437Z
fred_dot_u
<p>You have a too thick layer: to get straight lines, the plastic has to be squished together to some degree as it is pushed out of the nozzle. The result is a shape similar to a circle with the top and bottom cut. This works well until your layer thickness is more than 3 quarters of the nozzle diameter - above the "squishing" is practically nonexistent, and if you go above the nozzle diameter, there is almost no way to get the desired thickness out of the nozzle at all.</p>

<p>To aid in depositing the layers, it is <em>also</em> advised to demand a line width that is about 10 % larger than the nozzle diameter. As illustration, this is roughly what 0.4 mm extrusion width with 0.4 mm layer height (blue) and 0.45 mm extrusion width with 0.3 mm extrusion height (yellow) look like:</p>

<p><a href="https://i.sstatic.net/BzIa5.png" rel="noreferrer"><img src="https://i.sstatic.net/BzIa5.png" alt="enter image description here"></a><a href="https://i.sstatic.net/yZqG8.png" rel="noreferrer"><img src="https://i.sstatic.net/yZqG8.png" alt="enter image description here"></a><a href="https://i.sstatic.net/ElU6V.png" rel="noreferrer"><img src="https://i.sstatic.net/ElU6V.png" alt="enter image description here"></a><a href="https://i.sstatic.net/GPRyP.png" rel="noreferrer"><img src="https://i.sstatic.net/GPRyP.png" alt="enter image description here"></a></p>

CC BY-SA 4.0
2020-01-06T01:13:20.993Z
Now that's some awesome graphics! +1
Pᴀᴜʟsᴛᴇʀ2
CC BY-SA 4.0
2020-01-06T23:31:48.003Z
I would also check this answer as resolving the problem, but only one is allowed and I checked the one who answered first.
Perry Webb
CC BY-SA 4.0
2020-01-07T10:59:37.587Z
@PerryWebb the guideline is to check the answer which you think is the most helpful.
Trish
CC BY-SA 4.0
2020-01-20T15:29:04.807Z
Where did you get the images for this? They're awesome!!!!
Diesel
CC BY-SA 4.0
2020-01-20T15:29:52.690Z
@Diesel I made them with Fusion360
Trish
CC BY-SA 4.0
2020-01-24T15:49:13.657Z
They're awesome, I'll have to start playing with Fusion360 more!
Diesel
CC BY-SA 4.0
2020-01-05T14:55:49.030Z
2020-01-05T14:55:49.030Z
Trish
<p>I'm getting wavy lines on the first layer only in both the x and y direction identically.  The first layer is 0.4 mm with a 0.4 mm tip. The other layers are 0.2 mm.  I've tried changing the Z offset all the way from -1.2 to 0.5 mm.  I've tried changing the hot end leveling the heated bed.  None of these changes affected the wavy lines.  The waves have about a 1 mm period.  The printer is a German RipRap.  The material is ABS.  The heated bed is 110&nbsp;&deg;C.  I've tried the hot end at 220&nbsp;&deg;C and 240&nbsp;&deg;C.  So far, nothing has changed the waves.  </p>

<p><a href="https://i.sstatic.net/e74SF.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/e74SF.jpg" alt="enter image description here"></a></p>

CC BY-SA 4.0
2020-01-05T06:14:11.893Z
Are you sure they're actually supposed to be straight lines?
R.. GitHub STOP HELPING ICE
<troubleshooting><extrusion>
Wavy lines on 1st layer only
Perry Webb
# Wavy lines on 1st layer only

(Asked by: username_0 on 2020-01-05)

I'm getting wavy lines on the first layer only in both the x and y direction identically. The first layer is 0.4 mm with a 0.4 mm tip. The other layers are 0.2 mm. I've tried changing the Z offset all the way from -1.2 to 0.5 mm. I've tried changing the hot end leveling the heated bed. None of these changes affected the wavy lines. The waves have about a 1 mm period. The printer is a German RipRap. The material is ABS. The heated bed is 110 °C. I've tried the hot end at 220 °C and 240 °C. So far, nothing has changed the waves.

[![enter image description here](https://i.sstatic.net/e74SF.jpg)](https://i.sstatic.net/e74SF.jpg)

**Tags:** troubleshooting, extrusion
> **Comments:**
> **username_1**: Are you sure they're actually supposed to be straight lines?  

---

## 2 answers

### Answer by username_3 on 2020-01-05. Score: 5 | Accepted answer

You have a too thick layer: to get straight lines, the plastic has to be squished together to some degree as it is pushed out of the nozzle. The result is a shape similar to a circle with the top and bottom cut. This works well until your layer thickness is more than 3 quarters of the nozzle diameter - above the "squishing" is practically nonexistent, and if you go above the nozzle diameter, there is almost no way to get the desired thickness out of the nozzle at all.

To aid in depositing the layers, it is *also* advised to demand a line width that is about 10 % larger than the nozzle diameter. As illustration, this is roughly what 0.4 mm extrusion width with 0.4 mm layer height (blue) and 0.45 mm extrusion width with 0.3 mm extrusion height (yellow) look like:

[![enter image description here](https://i.sstatic.net/BzIa5.png)](https://i.sstatic.net/BzIa5.png)[![enter image description here](https://i.sstatic.net/yZqG8.png)](https://i.sstatic.net/yZqG8.png)[![enter image description here](https://i.sstatic.net/ElU6V.png)](https://i.sstatic.net/ElU6V.png)[![enter image description here](https://i.sstatic.net/GPRyP.png)](https://i.sstatic.net/GPRyP.png)

> **Comments:**
> **username_4**: Now that's some awesome graphics! +1  
> **username_0**: I would also check this answer as resolving the problem, but only one is allowed and I checked the one who answered first.  
> **username_3**: @PerryWebb the guideline is to check the answer which you think is the most helpful.  
> **username_5**: Where did you get the images for this? They're awesome!!!!  
> **username_3**: @Diesel I made them with Fusion360  
> **username_5**: They're awesome, I'll have to start playing with Fusion360 more!  

---

### Answer by username_2 on 2020-01-05. Score: 2

The general recommendation for layer height is to go no thicker than 75% of the nozzle diameter. Your post states 0.4 mm layer height with a 0.4 nozzle, exceeding the recommendation.

If your first layer is dropped to 0.3 mm, you'll fall into the recommendation, but the thickness is a reference for ALL layers.

> **Comments:**
> **username_0**: I'll try this out tomorrow. Hopefully, this is the answer.  

---

