Let's Talk All Things 3d for prop creation, Scan, Design, Sculpt (real and digital), Print and Finish

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Looking nifty greenmachines...saying that, I don't like large surfaces to be glued together (especially with CA glue). You really need to come sharp and clean putting those two parts together:eek:
I feel the same way. My plan is to make the edges negative and back fill the gap that results. The centers will be touching but not the hair thin edges. These are the locations (bottom first, then edges) that elephant foot / mushroom and cause uneven matching. Removing that little hair thickness line on all matching edges will allow a tight fit.

I have plenty to practice with so I may very well try adding vertical splines (threaded plastic rod or filament). I am going to use this one as my test bed for long print objects.
 
Now I am seeing the serious level of work that goes into print ready stl. I bought a blaster print from Buissonland and it was so prepped for prop makers that it had each material type separated. Wood handles, blaster body, flash hider, all separated so I can prep and paint each material type. The flash hider and barrel were so well designed as to allow me to just thread the two together using the threads already in the print. Separating this trident but still allowing for some alignment slots, minimal supports and scarring and with support rod holes....... not simple. Finding a great designer is like finding your favorite model kit company.

The elysium rifle from scornflake is that way, made for prop makers

Post in thread 'Elysium SMG Kit (or STLs)' Unlimited Run - Elysium SMG Kit (or STLs)

I have an uphill skill climb ahead.
 
COOLING THE BED AND PRINTER FRAME -

Did not know this was a thing, an issue, or even possible but I had a failed print, just a few lines, and found a solution for it.

I had been printing successfully for days and just pop, it fails to adhere the newest print to the bed, on layer one. The line was obviously taller and soon let go of the bed and started birdnesting. These are certainly signs that the gap between printhead and bed has increased.

I had to really put the thinking cap on as I had successfully gone from section to section of this Aquaman trident with no issues..... and this one was a REPEAT PRINT!!!!

I wasn't loading a new file, wasn't changing filament, nothing new, just print a second one. FDM printer, of course. I removed a beautiful print and set it to print another of the exact same part.

Because the print bed is temperature controlled, I could not see how it could go wrong as it clearly stated the same temperature as before, as well as on the printhead.

My part, just removed, had a very large print bed footprint. Lots of area covered. Hint: very well insulating the bed....

The ONLY thing different on this run was the speed at which I started a second run. So, I waited for the temperature to drop to waiting temp. and restarted just like all the previous runs had required due to me piddling around loading the new part file.

It was perfect.

Obviously, the spread of the heat in the bed and its support structure was affecting the shape of the entire printer. Even though the bed temp was being monitored by the thermostat, the heat in non monitored portions of the frame was different than the previous, cold start, run.

I allowed it to cool and then reheat from the same point as other prints and everything was back to normal.

One more trick in the toolbox......
 
COOLING THE BED AND PRINTER FRAME -

Did not know this was a thing, an issue, or even possible but I had a failed print, just a few lines, and found a solution for it.

I had been printing successfully for days and just pop, it fails to adhere the newest print to the bed, on layer one. The line was obviously taller and soon let go of the bed and started birdnesting. These are certainly signs that the gap between printhead and bed has increased.

I had to really put the thinking cap on as I had successfully gone from section to section of this Aquaman trident with no issues..... and this one was a REPEAT PRINT!!!!

I wasn't loading a new file, wasn't changing filament, nothing new, just print a second one. FDM printer, of course. I removed a beautiful print and set it to print another of the exact same part.

Because the print bed is temperature controlled, I could not see how it could go wrong as it clearly stated the same temperature as before, as well as on the printhead.

My part, just removed, had a very large print bed footprint. Lots of area covered. Hint: very well insulating the bed....

The ONLY thing different on this run was the speed at which I started a second run. So, I waited for the temperature to drop to waiting temp. and restarted just like all the previous runs had required due to me piddling around loading the new part file.

It was perfect.

Obviously, the spread of the heat in the bed and its support structure was affecting the shape of the entire printer. Even though the bed temp was being monitored by the thermostat, the heat in non monitored portions of the frame was different than the previous, cold start, run.

I allowed it to cool and then reheat from the same point as other prints and everything was back to normal.

One more trick in the toolbox......
So, again...stupid question from the noob: is the bed temp different than the printing head temp? My thought is yes, different...but I could be wrong.:unsure:
 
There is the nozzle temperature which melts the filament as it come off the reel and out of the "hot end". This is the "extruder" which lays down the filament. The bed can also have a temperature control. Originally not all did. The bed temperature is to allow the hot filament as it comes out of the extruder to adhere to the warm bed. A "cold" bed often did not allow the filament to stick properly and it would rise off the bed. Some times just the edges of an object would curve up off the bed so there was not an expected, level surface for future layers. Sometimes the failure was more dramatic. A cold bed creates a condition much like a "cold' solder joint if people are more familiar with that type of failure.
 
And that is why this issue really surprised me. The bed said the right temp, the extruder said the right temp but the print nozzle was obviously farther away from the bed than it should be. I let the whole machine cool and then reheat ONLY the extruder and the bed to the same temp as before and it was perfect.
 
I know it isn't the same physics but the easiest way to explain it is to lay your hand on cardboard and then spray water over your hand. The cardboard will puff and swell where your hand was not covering. The same applies to drying. The heat being held in the bed, only were the print is, causes the non covered areas to release heat faster, which causes the bed to warp. The highest temp is still controlled by the thermostat but not the even spread of that heat.
 
Just a few more temperature comments to consider when trying to plan a print or diagnose a failure. The bed temperature is only good for the first layer if you are printing a thick layer. If you have thinner layers the heat may permeate up - but most plastics we print with act as insulators. Ideally after the first layer you will be printing on the same type of plastic you are extruding. The hot extrusion will melt and adhere to the any adjacent layers below or beside the one being deposited. But print speed and object size comes into play in conjunction with localized layer size. With a large print there may be a long time lapse between when those adjacent layers where deposited - they may be at ambient temperature. If you are also printing fast - the amount of time available for the heat going into the new strand may be enough to melt the extruding filament with little excess heat to melt the adjacent layers. If you have a cooling fan running that will also reduce the adherence. The cooling fan is normally used to help with overhang and bridging - to help solidify the new strand where there is less to adhere to.
 
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