OK, it’s been a couple of months since I’ve posted on this topic, but I’ve learned a lot about 3D printing, which I’ve applied to this problem. I’ve combined what I’ve learned, with what all of you have suggested, and as a result, I’ve managed to get the parts to print, using Polycarbonite filament.
This will be a long post, but I’ll break it down into individual topics, covering what I’ve learned, and how I’ve solved the problems.
Learn how to describe your problem
First of all, you need to be able to describe the problem correctly, so that you can look at how to correct it. In my case, I found that when trying to print the cone-shaped insert for the cooktop knobs, I found that the base of the knob was printing just fine, but when the printer tried to print the stem, it appeared to me that the filament was simply too hot, and it appeared to be melting the previous layer.
I was dealing with the problem of not knowing what temperature to use for the bed, and for the filament. Even though I didn’t yet know how to solve the problem, it became clear that my problem was related to the temperature settings that I had chosen.
Thinking out of the box
Now that you know how to describe your problem, take a minute and think about different ways to solve the problem. I could have addressed the problem by trying different temperatures, but I had been trying that for the better part of 3 days, and had managed to get the print temperatures to work very well, except when the print area for a given layer was small enough to cause the filament to overwhelm the previous layers. So, I opted to look at the problem differently.
First, I thought about using a modifier to alter print behavior, using different temperatures, or just using different filaments, or adjusting adhesion using different bed adhesives, or even changing parameters to further alter printhead behavior. In the end, my solution was simply to invert the piece that I was printing, and enabling support.
By flipping the piece over, and enabling support, the entire printing process was different, yet the part was exactly the same, as were all the print settings.
So, remember that there are many ways to solve the problem, and there is no shortage of people that want to help. But, it’s hard to know which advice is good, and which advice is bad. Only you can cut through all of the information (some good, some bad), and methodically look into your options.
Before I leave this topic, I want to share that even though some of the suggestions that were given to me didn’t work, they were part of my education process, which opened my eyes to the many ways that the problem can be solved. I consider all of the information and suggestions to be sound, and helpful. But, the fact that so many people suggested different ways to solve the problem indicates that the biggest problem that you’ll face is that you’ll try to solve the problem by simply using different print settings, when in fact, you need to consider the print settings as only 1 part of the solution.
Solution
Using the Bambu slicer, I inverted the piece so that “the stem” was attached to the build plate, while the cone was suspended in the air. This method cannot be used unless I enabled support, but when support was enabled, instead of printing a single cylinder of filament, which was about 1.5" tall, I was printing the cylinder, along with all of the support structure. So, the time it took to print a single layer was much longer, which allowed the filament to cool enough between layers, that it would build correctly, additively, over time.
What type of support to use
I found that using standard support did not work well. The part would tend to release at about layer 131, out of 260. However, when I used Tree support, the part stayed adhered to the build plate, and the print completed (Some of the time).
What to do to get the part to stick to the build plate every time
At first, I used the trick of spraying hair spray onto the build plate. To me, this sounded silly, but it actually worked very well, causing the parts to stick to the build plate much better than without the hair spray. But, about 1 out of 3 of the prints would still fail when they release from the build plate prior to completion of the print.
So, I then tried using the 3D printer bed adhesive from Visionminor.com. This nanopolymer worked very well, and the parts would remain fastened to the build plate, allowing the print to complete correctly.
Implications of using hairspray for bed adhesion
Using hair spray to improve bed adhesion works very well. Although it did not work consistently for every print, I generally had great outcomes using this technique. But, I noticed that after I started to print, using the Bambu Labs Engineering plate, I could see that the hair spray seemed to liquefy just a little bit. Using the spray allows the parts to release from the build plate really well, but there seems to be a scenario where the plate gets hot enough to liquefy the hairspray, causing unpredictable results. The nano polymer did not have this effect on the build plate.
Coating the build plate with the nano polymer worked really well, and it generated very consistent results, print after print.
Why not use a modifier?
First of all, I did not know what a modifier is, nor how to use one of them. The suggestions that I received seemed to indicate that I needed to have some other part, which I could use to modify the shape, and printing steps for printing a piece that was proving to be problematic. But, investigating what a modifier is, and how to use them shed a lot of light on the matter, and I learned that modifiers are easy to use, and can prove to be very effective. They work like this…
With your mesh drawing (.STL File) loaded into Bambu Studio, you can right click on the object in question, and add a modifier. A modifier can be additive (or to modify the settings for an object), or be used to remove material.
Imagine if you had a piece to print, which was a rectanble of 20 cm x 20 cm x 5 mm thick. If this piece had a hole in it that you thought should be strenghened, you could simply add a modifier, in the shape of a cylinder. You add this shape, and then you move the shape so that it completely covers the area that you’d like to modify. Then, in Bambu Studio, you view the mesh drawing by Object, rather than as a “global unit”. When you do this, you’ll see that the part is now broken down into the main object, and an object that covers the area that you wan to modify. You could then set the infill for this area to 100%, causing the area where the hole is to be 100%, while the rest of the object might have a 15% infill percentage.
You could use this approach to slow down the printing of a specific area of your print, altering extrusion amounts, extrusion speeds, extraction characteristics, etc.
So, if someone recommends using a modifier, don’t be intimidated. View a video on YouTube, and give it a try.
In my case, I could have used a modifier, but in the end, the results were pretty consistent when inverting the part, so keep in mind that there is always more than one way to skin the cat.
Using a filament dryer
In one of the earlier posts in this thread, I mentioned that I was not using a filament dryer, or that my dryer may not have been delivering the best results. In the end, I send my SunLu dryer back to Amazon, and purchased a Creality filament dryer. And now, any time I’m going to print TPU, or PC, I use a dryer, and don’t start to print until the dryer shows RH at less than 20%. Now, I realize that there has been some disputing the accuracy of these Humidity ratings, and I accept that. However, whether the RH number is accurate or not, it is clear that by using the dryer, there is less humidity in the filament, and it delivers better and more consistent results.
