Welcome to the SeeMeCNC Community

I have only used PLA so far, and it is a pain. It seems that everyone is saying just add a fan and the jams stop , so far that is not the case. I now have a fan used to cool a CPU and it puts out a ton of wind. Now , with this my hot end doesn't even get up to temp, I got around that by puttin some tape on the fan to redirect the air, i still get jams though. I am thinking a resistor on the fan to slow it down a bit but IDK how thtat will work. Is there something I'm missing?

This is a case of more is Not better! You are likely cooling the entire hot end too much. Atkins fan direct edit at the barrel will keep it cool and allow the hot end to stay hot. Make sure your temps are good too, too hot and you'll have problems with PLA.

Regards,
Michael

any recommendations for a new fan?

A 40mm square fan is a good size, can be mounted on the carriage and provides a good flow.

Thats what I had originally, but it didn't put out enough flow

Works for many of us. What sorts of problems are y having?

I mounted it right on the edge of the extruder , like everyone else but i'd still get jams, I tried turnign down the temp but then I got bad extrusion, I orignally had a different 40mm fan but it broke then I switched to a new one which put out less flow, I am going to try a fan I stole from a gpu tommorrow which should give me decent flow and good control

You don't need very much airflow, just enough to disturb the air around the thermal break.
What temperature are you trying to print at?

sadly I could'nt tell you, i have been guessing at that the entire time, When ever the extrusion comes out well is where I print

, just remembered , only have half of my ptfe is there, maybe it gets caught on there?

stole the copper heat exchange that brought heat from a processor to a radiator on an old laptop, wrapped it around the PEEK , used a 40mm fan and so far no jams. I probably just jinxed myself

(Not a) Stupid Question: What do you wire the fan to? I see so many references to fans, what are you wiring it to?

Smart Question: If someone answers the above listed question, where is the best place to put this instruction? A category called Supplemental Docs?

John, (not a) stupid answer: "it depends"!

If you are running a Mach based setup, you are likely just going to wire the fan direct to the power supply with an on/off switch. You can do this on Arduino based systems as well. However, RAMPs and RAMBo both support fan control and in this case you wire the fan to the specified pin/s. The specific board's configuration information will tell you which. You also have to enable and configure this in your firmware (Sprinter, Marlin, Repetier, etc).

cheers,
Michael

I wire mine to the PSU directly and run my temp (velleman) through my spindle interface on my 4-axis board

mhackney wrote:John, (not a) stupid answer: "it depends"!

If you are running a Mach based setup, you are likely just going to wire the fan direct to the power supply with an on/off switch. You can do this on Arduino based systems as well. However, RAMPs and RAMBo both support fan control and in this case you wire the fan to the specified pin/s. The specific board's configuration information will tell you which. You also have to enable and configure this in your firmware (Sprinter, Marlin, Repetier, etc).

cheers,
Michael

Thanks! I'll take a look. I'm going to the build event in March and will build it there. I'm picking up a fan and hope to include it during that weekend build.

The first thing I think you should do is buy a thermocouple multimeter - I got mine of ebay and it was really cheap. Even if it is not that accurate it will still give you guidance to what temp your hot end is. If you are stabbing in the dark with the hot end temperature there will never be any way to get your machine to consistently print.

I have had one incident of jamming with PLA and it had a 40mm fan on the barrel and it was because I let my hot end get super hot - 220C (super hot for PLA). I usually print around 180C (these are temps recorded from a not super accurate multimeter thermocouple) and the 40mm fan 'wafts' air across the PET barrel - it literally just moves air past. The fan has little effect on the hot end temp.

I hope this helps - I hear people with PLA problems and really don't get it. I love the stuff.

Thanks, i have it working now, 3 days without a jam. Now my issue is gcode, My infill doesn't touch my perimeters, leaving a gap and making my perimeter feel weak. Any ideas? At first I thought it was backlash, but now I have the hose clamp mod on and I have the same thing.

Tom, lots of things contribute to insufficient infill. A lot can be learned by diagnosing what it looks like. Post a good photo if you can. Backlash issues will usually over-run on one end and incomplete on the other on the afflicted axis. If the problem exists very uniformly at both ends of the infill, it is likely not mechanical backlash.

In this case, make sure you are delivering the correct amount of filament. Measure your filament diameter and put that in you slicer app. Also make sure you have calibrated your extruder and that it is not slipping. Make sure the nozzle orifice diameter is set properly. Slic3r has an Extrusion multiplier setting onm the Filament Settings tab that allows you deliver more or less filament. Usually it is set at 1 so up it to 1.1 and see what happens. And make sure to check your Layer height - it should be smaller than your orifice diameter so the extruded filament gets squished.

Let us know what you find.

Cheers,
Michael

Thanks, I think somehow the extruder is off, instead of calibrating it , I set my extrusion multiplier to 2 and so far my calibration print is looking good

I printed a 20 mm cube and it came out to be 22mm, while my nickle test, it doesnt fit ,in either sides. any ideas?

Calibration, calibration, calibration! Calibrate your axis movement then the extruder. Also make sure you don't have backlash anywhere. Easy to check with a dial or test indicator. You can pick one up for cheap on eBay and some of the import tool places.

cheers,
Michael

Just for the record, I am using a 12 volt 40mm fan from Radio Shack that pushes 7.7cfm wired into the RAMBO board and I usually run @ about 60% - 80% speed and haven't had a jam since I installed it (I was having PLA jams every print before hand)..