One of the most popular operations I show users when I install a Stratasys FDM printer with Insight software is the delete support function. This is a necessity to build parts that will need less post processing time. This feature is mostly used to delete support out of holes that run horizontally thru a part. If you have long through-holes or complicated passageways, it is hard for the support material to be washed out of those areas in the bath. Most of the time we end up deleting the support out of holes for self tapping screw holes or holes that will be tapped for screws. By deleting the support we may be adding some time to the post processing because you may want to print the holes under size then drill or ream them out to the final size. This time is minimal compared to waiting for the part to come out of the wash station, which can sometimes be overnight.
Deleting Support Material Example
The file I will be highlighting in this blog is already on your computer if you have the Insight software loaded, making it easy to follow along. When you initially load the software onto your computer Stratasys added some sample STL files for you to play around with. None of them are that great, but they serve as examples in some of the advanced classes we teach about using Insight. The file I will be using is the case file and on my computer it is located here C:\Program Files\Stratasys\Insight 11.0\train.
I use this part file at my installation training to show users what a bad STL file looks like. This is a bad file because of the large faceting on the larger radiuses. This is an example of not saving at a high enough resolution. The most important part of 3D printing is starting out with a good file. Bad part file means bad printed part. The part opens in is the orientation we want, with the screw bosses running horizontally. My settings will be solid part interior, smart support at the .010” slice height. I will be showing you how to delete the support out of both screw bosses because the bottom one is a little trickier. I green flag the part and select the view all layers button it should look like the screen shot above. We can see the support tower now running up through the bosses. Using our select layer tool I can select a layer around the middle of the top screw boss. We can now see just that one layer. I press the F5 key to look at the part from the top and zoom into the area of the screw boss like below. Using the page up and down I can scroll through the layers to find the layers of support within the top screw boss we want to delete. I find the top layer of support inside the boss at layer number 241. We will now make a range of layer to view and hide the rest. Once I am at layer 241 I select the range top button. This will take the height dimension of that layer. Then we page down to the bottom layer of support within the screw boss, this should be at layer 230. Select the range bottom button and now we have our range set. We can now select the view range tool. Your view should look like this. I deleted the toolpaths to make it easier to see. Now I find the delete operation under edit/delete at the top of the page. It should be set to delete curves. In the insight software any closed contour is referred to as a curve. I want to use my selection filters on the bottom right of the screen so I only select the support contours. Select the down arrow box and then select system support curve. Now click and drag your curser over just the support contours within the screw boss. They should turn white. Hit okay and they are gone. Now that they are gone you don’t want to use the green flag because it will just put the support back. The software will ask to redo the model toolpath and we do this by selecting the toolpath icon. Now we will delete the support from the bottom screw boss. As you page down thru the boss you will notice at layer number 38 the support material is connected to the support tower on the outside of the boss. This is more obvious at layer number 36. To remove the support from the inside of the boss and not disturb what is on the outside we will need to use the delete tool again. This time we want to set our delete tool to segments connect instead of curves. This operation will delete whatever we select and connect whatever is left. We start the same as the other boss we select our range. It should be from layer number 31 to 42. Now view the range and change the view to the above view. Now we make sure our selection filter is still set to system support curves and just click and drag to select the support line segments inside the screw boss. It should look like the first screen shot below. First when it is selected, then with the support curve segments deleted and connected just inside the counter sunk area of the screw boss. Then the final screen shot is layer number 40 with the toolpath reprocessed and the toolpath shaded. Shading the toolpath is done by going to tool path at the top of the screen and selecting shade tool path. You have now deleted support from your model.
There are a few disclamers when you are doing this type of operation. Deleting support out of hole sometimes makes the hole more oblong shaped. This is because we are not supporting the top of the hole properly, we may get some drooling inside of the hole. This is fine if you are drilling or tapping the hole anyways. I recommend starting with a small block about one inch square. Add some holes, delete the support material out and print it out. This will give you a little practice to see what will happen before you move on to the real part.