<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.stack.imgur.com/e74SF.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/e74SF.jpg" alt="enter image description here"></a></p>

[{'answer_id': 11682, 'author': 'fred_dot_u', 'author_id': 854, 'author_profile': 'https://3dprinting.stackexchange.com/users/854', 'pm_score': 2, 'selected': False, 'text': "<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>\n\n<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>\n"}, {'answer_id': 11683, 'author': 'Trish', 'author_id': 8884, 'author_profile': 'https://3dprinting.stackexchange.com/users/8884', 'pm_score': 4, 'selected': True, 'text': '<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>\n\n<p>To aid in depositing the layers, it is <em>also</em> advised to demand a line width that is about 10\xa0% larger than the nozzle diameter. As illustration, this is roughly what 0.4\xa0mm extrusion width with 0.4\xa0mm layer height (blue) and 0.45\xa0mm extrusion width with 0.3\xa0mm extrusion height (yellow) look like:</p>\n\n<p><a href="https://i.stack.imgur.com/BzIa5.png" rel="noreferrer"><img src="https://i.stack.imgur.com/BzIa5.png" alt="enter image description here"></a><a href="https://i.stack.imgur.com/yZqG8.png" rel="noreferrer"><img src="https://i.stack.imgur.com/yZqG8.png" alt="enter image description here"></a><a href="https://i.stack.imgur.com/ElU6V.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ElU6V.png" alt="enter image description here"></a><a href="https://i.stack.imgur.com/GPRyP.png" rel="noreferrer"><img src="https://i.stack.imgur.com/GPRyP.png" alt="enter image description here"></a></p>\n'}]
['https://3dprinting.stackexchange.com/questions/11679', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/15075/']