What a difference three thou makes

With the PP3DP filament having proven itself admirably in the Stratasys, I ran more parts with the material and set up a job consisting of a little box to hold ER-16 collets and a paintball gun trigger frame.  Since I don’t like to have the machine powered up and sitting idle at full temperature for long periods (thereby cooking the filament), I try to adjust the parameters so that the job will complete during the day, allowing me to immediately start up a new job, or power down the machine.  There’s a few methods that I use for this – I can add or remove parts from the job, I can adjust the infill density (turning on the crosshatch options for a faster ‘sparse’ infill), or I can change the layer thickness (thinner layers give more precise parts but take longer).  For this particular job, I wanted to use a sparse infill to conserve material, and wound up changing the layer thickness to 0.007″ down from the normal 0.010″.

This adjustment of the layer thickness also affects the base layers (‘raft’ in RepRap speak), and since the foam build base I currently have in the machine is getting a bit ratty, I increased the number of base layers from the normal 5 to 10 for a total base height of 0.070″ to traverse the increasingly rough terrain of the foam (I have a box full of new foam bases – I should just replace the darn thing).  While I had run 0.007″ layers with the PA-747 and MG47 materials, I had never done so with support material.  I watched the base layers progress to see how well they’d form with a smaller slice height.

Blurry photo - I have 'new camera syndrome' (also known as 'still trying to figure out what all these buttons do')

On the right side of the base, you can see a bit of waviness on some of the roads in the center.  As the nozzle would make a pass, the ‘wall’ that was being formed would flop slightly to the side – the long straight lines of the roads didn’t help the wall stiffness any.  As the freshly deposited topmost road cooled and contracted, the wall would return mostly to normal shape, but some waviness remained.  On the left side, the top layer of the base is being laid down, and the support material actually started ‘bunching up’ in spots, resulting in a raised, rough surface.  I knew this would probably cause the model to become too infused with the support to allow the two to separate easily, but I let it run anyhow.

Poor adhesion between the model and base

When complete, I had significant warping and lifting on the corners of the trigger frame part, though support for holes and overhangs worked beautifully.  The poor adhesion to the base could be due to the concave surface on that face of the part – rather than having a solid face, the support layers under the trigger frame are an open crosshatch, so there’s not as much contact area.  The box halves fared better, though I had highly variable adhesion to the base layer (rotten at corners, yet fused together where I had roughness on the base layer).

Although I hadn’t run the MG47 with support, I wondered if the lower die swell of the MG47 helped provide such good results when running at a 0.007″ slice height.  I realized that I had never checked the die swell of the P400S support material, so I finally checked it – a whopping 0.020″!  It makes sense that the support material wouldn’t act as kindly with such a small layer height – it wants to swell up, as it’s being ‘smeared’ to a road width much greater than the road thickness.

At this point I wondered if newer algorithms and flow curves present in Insight might make 7 thou base layers behave a little better.  Unfortunately, Insight never had support for the 1600 (and official support for the entire FDM thousand series machines was dropped at the end of the version 6 lifespan), though it can generate output for the 1650.  Given that there are a number of 1650s still in use, yet I’m the only one I know of with a 1600, it was possible that differences between the two are minimal.  In looking through generated output from QuickSlice for the two models, it looked like parameters were very similar (though the 1650 is run a little faster).  I crossed my fingers, set up Insight to send to a 1650 and let it rip on a Mendel test part at a 0.010″ slice height.  Wonder of wonders, it ran without a hitch – a part that would take an hour in Quickslice would take only about 45 minutes through Insight!  I set up a whole plate of Mendel parts, and it ran equally well.  I then tried a small part at a 0.007″ slice height in Insight – it ran fine, so perhaps having a large surface area for the base is an issue.  Insight also has several support styles available, so I’ll need to play with those settings as well.

12 thoughts on “What a difference three thou makes

  1. On your trigger, I’ve had several parts that the part geometry wasn’t liked by Stratasys, due to a shollow curved surface in Z. I usually try to put those on the top of the build, but your part that isn’t possible. If you tip the part up on one end in Z, it will track the fine (slow) curves better, but use more support.

    Glad the Insight is working for you (and me too…).

    John

  2. Yeah, it seems supporting curved surfaces in Z is rather tricky – I wonder if the soluble support is deposited differently, as full contact between the two materials is just fine in that case?

  3. The only soluble supports parts I’ve run were years ago on a Dimension SST. I had also run the same parts on a BST. As I recall the support structures looked identical, but I didn’t mic them.

    It may be neat to have a ‘standard’ part and run it on as many machines as possible just to check stuff like that. And save the part intact for future comparisons.

    John

  4. Standard parts is precisely what I’ve been pondering, and have an attempt at such a thing running now. But I’m not sure what an ideal test part consists of…

  5. I just bought a used Stratasys Dimension SST but it didn’t come with the Catalyst or Insight software. Are there any other options for generating Stratasys build files?
    netshapeparts at live.com

  6. Hello, Michael.

    Kwartzlab is a makerspace in Kitchener, Ontario, Canada. And we just got 2 Stratasys FDM 2000s, dating from 1997. They power up just fine, but we can’t print anything yet, as we don’t have the driver software.

    My web research indicates that we should get a copy of “Insight”. And you have successfully used Insight with your FDM 1600.

    So I wonder if you can help us. What’s the best way for us to get a copy of Insight?

    Thanks in advance,
    Doug Moen / http://www.kwartzlab.ca.

  7. Is there a way to remove/change the base layer? I am working with the Fortus 250mc and Insight.

    I only have a limited number of boards and every print leaves a thin layer of model material on the board which can not be removed.

    Thank!

  8. It leaves model material? That’s odd – I think it should only be leaving support material as the first layer… You’re running P430 and SR30 for model and support material on the 250mc, correct? I’ve heard of people ‘refreshing’ the bases with a wipe of acetone.

  9. I am running a 250mc. Indeed, the first layer is always model material. An obnoxious and totally unnecessary step. According to my sales rep, it serves no purpose other than to render the bases non-reuseable.

    A sharp utility blade and some patience is the only solution that I’ve been able to find. It also helps to do it while the base is still warm from printing. Otherwise it can be extremely difficult to separate from the ABS base.

    It would be nice if there was a base made out of a material that won’t permantly adhere with the model material.

  10. My guess is that the model material adheres better to the base than the support material does, and this is done as an extra hedge against warp and curling. You could try using a wipe of a silicone spray to help act as a release agent, but that may make it too easy to remove. Alternatively, it sounds like a bunch of reprap users have had good success with using Ultem sheet as a base.

  11. Hi Doug,

    I’m new on here and I just purchased a FDM 1650 and It didn’t come with the software (Insight) and I’ve been trying to track it down and seems to be I cant find it any where. I was wondering if you have found it yet or know where i can get a copy of it. If you could help me out that would be sweet!!!

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