Flow rate (Page 1 of 2)

Don't use a cylinder.  The walls come out wider because the thread is compressed on the inside and stretched on the outside going around the bend, and the flat caliper is going to bridge the curve to a small amount.  Always use something with flat sides.

I just went through this today, as I was having issues.  Instead of downloading something from Thingiverse, I made my own test piece that has walls at right angles to each other as well as 45° angles, curves and even a hole in the center to test for roundness.

Here is what the final output looks like after I tweaked the flow rate and the extruder steps.

The stringy things between the cylinder wall and the outer wall was a result of my Retraction setting.  I had the "Extra Length on Retract" set to .5mm, after I put it back to 0mm, the little stringy things went away.

I've attached my test  model.  If you want to print it, set the Vertical Shells: Perimeters to 1, Horizontal Shells: Top Solid Layer to 0, Bottom Layer to 3, and Infill: Fill Density to 0.  Slice & print. 

You can also use it to calibrate your X & Y steps.  The left side is 50mm, the square notch is 10x10mm, from the left corner to the notch it's 20mm, the hole diameter is 20mm, and the height is 10mmm

One thing that might make holes is too much retraction.  Do they always happen at corners or layer changes?

What is your retraction settings?

Let me preface this with "I've never had any luck using PLA".  But having said that there are 2 possible problems here, or a combination of the 2.   

1.  The temperature of the PLA is too low, so the layers don't stick to each other.  Increase the temperature 5°C at the time and see if it helps.
2.  The extrusion is too thin, so you have to adjust the flow rate, or the default extrusion width (or both).

yea my extruder is extruding about 33mm too much so i have to calibrate it im just having trouble finding the file with arduino also i was originally printing at around 195 when i did this so yea i tried upping the heat with no difference and also where do i go to adjust the width of it extruding

*slams face on desk* hahaha
Sorry none of us asked you that. Yes...when printing PLA, a fan is needed for sure. I posted this very recently on here.
Things I bought:
*40mm fan. available on Amazon.com for around $4 up
*A desk fan (to print a PLA fan mount, you will need a fan...catch 22)
*12v power brick to power the 40mm fan
*3 pin extension cable. Without soldering to your board and making a massive error such as rendering your printer brain dead, buy this so it will reach your supply
*3 pin to 4 pin adapter
*(optional) 3 pin splitter in the event you want to power more than one fan

1) download this http://www.thingiverse.com/thing:38129  it is quick and easy to make. I printed several just to have on the side.
2) Print. I prefer 60% infill to help prevent any wobble
3) Mount to the wooden block and screw fan to print with
4) Toss on the 40mm fan and tighten to prevent wobble (too tight and the print will crack)
5) Wire up the 40mm fan
6) Repeat all steps excluding 1

Of course...if you have a case, it is recommended you remove it. You dont want too little or too much air hitting the filament as it is extruding. But...BUT! you could eternally having the desk fan on when printing PLA. It would take up space and be and eyesore, but would bypass the given steps I took.

how small of a desk fan are we talking about?

My retraction acceleration is currently set at 3000.00, that's the only thing I could find in repetier that was obviously a retraction setting.  This is my first experience with a 3d printer, sorry for being such a complete noob.

Alright I tried printing a single walled thing again first with an extrusion multiplier of 1 and retraction set at 1.00mm that ended with a print without a single hole, but a thickness of .69mm (left) and again with extrusion multiple of .61 that ended with giant holes and a wall thickness of .60 in the areas with only small holes. (right)

doesanyone know where i can find female connectors for the for the board for the bed and thermistor