String occurs when the print head stops laying down filament in one place and jumps to another place to begin laying down filament. As it travels, a small strand of filament is drawn across the gap from one location to another... much like a spider spinning a web.
I first noticed the issue when creating an object with Durable Clear using 50 Micron layers and Solid fill. Contacting M3D support, I was told to try less resolution and less infill. That seemed reasonable from my experience with other printers, so I decided that if choosing a resolution and infill could remarkably alter the final output quality I wanted to know more and perhaps find my "go-to" setting for the Tough 3D materials.
I am now committed to testing each combination of settings to see how they affect the final outcome. So far, I have tested three settings and I actually can see some quantifiable results. I have not, as yet, gone back to the 50 Micron / Solid Infill because that setting demands a LONG print time. Instead, remembering the result with the Durable Clear, I have chosen settings that would help me to see if there is a difference with shorter print times.
Because the Durable Clear does not photograph well, I have chosen to run the tests using Tough 3D Ink Utility Grey. My method of evaluation is to use a photo copy stand with a single light to one side that will emphasize strings and other surface issues.
Because I am convinced that the M3D Micro is a perfect 3D printer for crafters and those that enjoy sewing and fabric construction, I chose to design a piece that could be sewn onto a garment or fabric accessory. It is intended to be printed in a flexible material and Tough 3D Ink is perfect for the job. It's a simple design just to demonstrate the concept.
Stringing Test #1: 250 Microns / Low Infill
Based on the suggestions from M3D support, my first test settings were 250 micron layers with Low infill. Clicking on the image will allow you to see it at full resolution. Remember, I am purposely lighting to accentuate even the most minor of flaws.
|250 Micron Layers / Low Infill Setting|
|Stringing Isolated to one quadrant|
It seems to be isolated to two strings in a single quadrant as marked in the above image. Stringing was limited to a single string between each affect petal. I would call this a very successful print with negligible stringing. So, what of the other tested settings?
Stringing Test #2: 300 Microns / Hollow Thick Infill
Base on the first test, I decided to lower the quality settings on both fronts. I moved up to 300 micron layers and took the infill setting down to Hollow Thick. While I was amazed at the over quality at his setting, I definitely could see some stringing issues.
|300 Micron Layers / Hollow Thick Infill|
So now I went in the other direction, I used a setting of 150 Microns with Medium Infill to bracket the 250 / Low test.
Stringing Test #3: 150 Microns / Medium Infill
This is the last test I will include in this post. But, it will not be my last test in searching for an optimal setting to reduce stringing with Tough 3D Ink using this particular design. Interestingly, while stringing certainly exists, and perhaps as much as the 300 Micron / Hollow thick test, it seemed to be confined more to the outside perimeter of the piece.
|150 Micron Layers / Medium Infill|
One of the things you will find about my approach to 3D printing is that I don't mind the time and materials that it takes to help all users have the best 3D printing experience. Not only do I personally enjoy it; but, it helps our students to avoid unnecessary and needless frustration. I know that the ability to print in flexible material is going to really appeal to our students. So, it's important for me to learn as much as possible about its characteristics. And, I hope it is helpful to you as well.
I am very impressed by the M3D Micro and if I can help others have the same positive experience with it as I am having, then I will be one happy camper! Keep looking for updates!