That First 3D Print – Part 5, The First Minute Of A 3D Print Is The Most Important

THE FIRST MINUTE OF A 3D PRINT IS THE MOST IMPORTANT
Usually you can tell in the first minute or so, if your 3D print is going to be okay, but there are problems you won’t know about until it’s finished or at least not until it’s well under way.  Some problems you’ll recognize in the first minute of a print are: how well the plastic is flowing from the nozzle and how well is the plastic sticking to the build surface?  If the flow of the plastic seems too slow, among the reasons are: it could be the filament flow rate set too slow or if there is no flow at all, there could be several reasons for this.  So, beside flow rate, the simplest reason there might not be enough plastic flowing out the nozzle could simply be because the plastic hasn’t primed the nozzle yet, meaning that the plastic hasn’t reached the tip yet and could be solved by just having a little patience.  If plastic doesn’t appear reasonably soon, you should hope that it is, is only because the nozzle is set too close to the bed.  Why should you hope this is the problem?  Because it’s a simple fix.  All it would take to correct is an adjustment to the distance between the bed and nozzle, so there is enough of a gap between them to allow the plastic to get out.  Any of the several other reasons there might be no plastic coming out of the nozzle are more serious; such as the nozzle is clogged, but I’ll talk more about that later; or the extruder is not feeding the filament to the hot end, either because the wheels of the extruder don’t have tight enough grip on the filament or they are worn down; the filament has been ground away, stripped or worse, the motor of the extruder has failed; or your best-case scenario would be, you’re out of filament.  But, I think that would be an obvious one.

 

YOU NOTICE THERE’S A PROBLEM WITH YOUR PRINT
Let’s assume your FDM printer has finished printing but you’ve noticed there’s a problem with the print.  Let’s say the problem is a minor one, such as stringiness.  That’s fibrous plastic webs between open parts of the print.  These could be caused by your retraction settings; either the printer is retracting the filament too slowly or not retracting it far enough.  It could also be the nozzle temperature is too high or movement speed needs adjusting.  In terms of 3D printing, ‘movement’ refers to when the printhead ‘moves’ between parts of the print while intending NOT to extrude any plastic from the nozzle.  Otherwise, if the hot end is supposed to be emitting plastic, it would be known as the “print speed.”

 

BE A HOT HEAD
If the layers of your print don’t seem to be sticking together well and/or you can easily snap the object apart along any of the layer lines, you probably didn’t have the nozzle temperature set high enough.  You could correct this by increasing the nozzle temperature higher about five (5) degrees and reprinting the object.  If the problem persists, try another five degrees and print again.  This, by the way, is a common method for finding correct temperatures settings: trying five-degree increments, plus or minus and reprinting the object(s) until the correct temperature is found.  A nozzle temperature set too low can also result in a stringy appearance of “floor” surfaces.  Too low a nozzle temperature could also cause a grinding and/or slippage of the filament in the extruder, because the plastic cannot melt fast enough to keep up with the filament feed.  So, it stands to reason that grinding and/or slippage can also be caused by the extruder trying to feed the filament too fast to the hot end.

 

STAY IN LINE AND KEEP A GRIP
Another common problem is layer shifting or misalignment.   We’re talking about one or more layers offset from other layers or from all the previous layers.  This can be caused by a few things.  A shaky, poorly built machine can cause layers to misalign with the others.  Also, a snagged filament spool can hinder a printheads movement enough to cause layers to shift and if not fixed soon enough could stop the filament feed altogether.  A snagged spool can be caused by not paying attention the filament as it goes between the spool and the machine.  It can get caught on something or twist up before reaching the extruder.  But another more common way spools get snagged is from allowing the free end of the filament to dangle loosely.  If a grip is not maintained on the free end of the filament, it is likely to wrap itself back around the spool and loose loops of the plastic can and likely will flop over the free end.  If this happens undetected, the next time this spool is used and the situation is not corrected before loading it into the extruder, the filament WILL during printing, eventually draw tight, wrapped under impending loop(s) of filament.  The best that a person can do to keep this from happening is, immediately after unloading a spool of filament from a printer is either clip or tape the loose end to the spool itself or tuck the loose end through one or two of the numerous holes around the edge of the spool.

For the other parts of the series:

Part 6: It’s Serious, But Don’t Get Discouraged

Part 4: You Made Your Bed, Now You Can Print On It

Part 3: What Will You Print First?

Part 2: The 3D Printer Does The Labor

Part 1: The Maker

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Darren Hughes

Darren is a Nerd/Jock hybrid. In fact, he maybe the original nerd. In the '60's, he and his Sister were certainly among the first Trekkies, having pretended to be the crew of Enterprise at night (after watching the original series during it's inaugural run) and playing little league in the day. Darren holds a few college degrees. One of them for Engineering and another for Computer Networking. He's always been a fan of learning and technology. Darren has only been 3D printing for a couple years and still considers himself a novice. It is his hope for this blog site to share what he learns as he goes with other beginners, to save them time and hassle finding the best 3D printing and avoiding the worst.