GrabCAD Print Software, Part Two: Simplify Set-ups, Save Time, and Do Cool Stuff You Hadn’t Even Considered

You haven’t really lived in the world of 3D printing until you’ve had a part fail spectacularly due to open faces, self-intersecting faces or inverted normals. Your part ends up looking more like modern art than technical part. Or perhaps the design you have in mind has great geometry but you wish that some parts could have regions that are dense and strong while other regions would work with minimal infill.

In Part One of this blog post about GrabCAD Print software, we covered the basics of setting up and printing a part; now we’ll look at several of the advanced features that save you set-up time and result in better parts.

Behind the Scenes Repairs

Stratasys GrabCAD Print software, available as a free download, is crafted for users setting up solid models for 3D printing on Stratasys FDM and PolyJet printers. Once you’ve started using it, you’ll find one of its many useful advanced features is the automated STL file-repair option.

Most people still create solid models in CAD software then convert the file to the industry-standard STL format before opening it in a given 3D printer’s own set-up software. Every CAD package works a little differently to generate an STL file, and once in a while the geometry just doesn’t get perfectly meshed. Triangles may overlap, triangles may end up very long and very skinny, or the vector that signals “point in” or “point out” can get reversed.

Imported STL file, with GrabCAD Print ready to automatically repair errors. PADT image.

Imported STL file, with GrabCAD Print ready to automatically repair errors. PADT image.

Traditionally, the 3D printer set-up program reacts to these situations by doing one of two things: it prints exactly what you tell it to print (producing weird holes and shifted layers) or it simply refuses to print at all. Both situations are due to tiny errors in the conversion of a solid CAD model to a tessellated surface.

GrabCAD Print, however, gives your file a once-over and immediately flags sections of the model in need of repair. You can see a color-coded representation of all the problem areas, choose to view just some or all, and then click on Automatic Repair. No hand-editing, no counting layers and identifying sections where the problems reside – just a click of the virtual button and all the problem regions are identified, repaired and ready for the next processing steps.

CAD vs. STL: Do So Much More with CAD

GrabCAD Print also uniquely allows users to bring in their models in the original CAD file-format (from SolidWorks, Autodesk, PTC, Siemens, etc.) or neutral formats, with no need to first convert it to STL. For FDM users, this means GrabCAD recognizes actual CAD bodies, faces, and features, letting you make build-modifications directly in the print set-up stage that previously would have required layer-by-layer slice editing, or couldn’t have been done at all.

For example, with a little planning ahead, you can bring in a multi-body CAD model (i.e., an assembly), merge the parts, and direct GrabCAD to apply different parameters to each body. This way you can reinforce some areas at full density then change the infill pattern, layout, and density in other regions where full strength is unnecessary.

Here’s an example of a SolidWorks model intended for printing with a solid lower base but lighter weight (saving material) in the upper sections. It’s a holder for Post-It® notes, comprising three individual parts – lower base, upper base and upper slot – combined and saved as an assembly.

Sample multi-body part ready to bring into GrabCAD Advanced FDM. Image PADT.

Sample multi-body part ready to bring into GrabCAD Advanced FDM. Image PADT.

Here was my workflow:

1 – I brought the assembly into GrabCAD and merged all the bodies, selected an F370 Stratasys FDM printer, chose Print Settings of acrylonitrile butadiene styrene (ABS) and 0.005 inches layer height, and oriented the part.

2 -To ensure strength in the lower base, I selected that section (you can do this either in the model tree or on the part itself) and opened the Selection Settings menu at the right. Under Body>Advanced, I chose Solid Infill and slid Rigidity to High.

3 – Then I selected the upper base, chose Hexagram, and changed the Infill Density to 60%.

4 – Lastly, I selected the upper slot section, chose Single Dense, and changed the Infill Density to 35%.

5 – With all three sections defined, I clicked on Slice Preview, sliced the model and used the slider bar on the left to step through each section’s toolpath. For the screenshots, I turned off showing Support Material; the yellow bits indicate where seams start (another parameter that can be edited).

Here is each section highlighted, with screenshots of the parameter choices and how the part infill looks when sliced:

Lower base set up in GrabCAD to print Solid; sliced toolpath shown at right. Image PADT.

Lower base set up in GrabCAD to print Solid; sliced toolpath shown at right. Image PADT.
Upper base set up in GrabCAD to print as Hexagram pattern, 60% infill; sliced toolpath shown at right. Image PADT

Upper base set up in GrabCAD to print as Hexagram pattern, 60% infill; sliced toolpath shown at right. Image PADT.
Upper slot section set up in GrabCAD to print as Single Dense pattern, 35% infill; sliced toolpath shown at right. Image PADT.

Upper slot section set up in GrabCAD to print as Single Dense pattern, 35% infill; sliced toolpath shown at right. Image PADT.

So that you can really see the differences, I printed the part four times, stopping as the infill got partway through each section, then letting the final part print to completion. Here are the three partial sections, plus my final part:

Lower base (solid), upper base (hexagram) and first part of upper slot (single dense), done as partial prints. Image PADT.

Lower base (solid), upper base (hexagram) and first part of upper slot (single dense), done as partial prints. Image PADT.
Completed note-holder set up in GrabCAD Print, Advanced FDM mode, weighted toward the bottom but light-weighted internally. Image PADT.

Completed note-holder set up in GrabCAD Print, Advanced FDM mode, weighted toward the bottom but light-weighted internally. Image PADT.

Automated Hole Sizing Simplifies Adding Inserts

But like the old advertisements say, “But wait – there’s more!” Do you use heat-set inserts a lot to create secure connections between 3D printed parts and metal hardware? Planning ahead for the right hole size, especially if you have different design groups involved and fasteners may not yet be decided, this is the feature for you.

Sample part set up for easy insert additions, using Advanced FDM in GrabCAD Print. Image PADT.

Sample part set up for easy insert additions, using Advanced FDM in GrabCAD Print. Image PADT.

In your CAD part model, draw a hole that is centered where you know the insert will go, give it a nominal diameter and use Cut/Extrude so that the hole is at least the depth of your longest candidate insert. Now bring your part into GrabCAD Advanced FDM (soon all these features will be available in a single Model Interface) and go to Selection Settings in the right-hand menu.

This time, click on Face (not Body) and Select the inner cylindrical wall of your hole. Several options will become active, including Apply Insert. When you check that box, a new drop-down will appear, giving you the choice of adding a heat-set insert, a helicoil insert or a custom size. Below that you select either Inch or Metric, and for either, the appropriate list of standard insert sizes appears.

Automatic hole-resizing in GrabCAD Print, for a specific, standard heat-set insert. Image PADT.

Automatic hole-resizing in GrabCAD Print, for a specific, standard heat-set insert. Image PADT.

Choose the insert you want, click Update in the upper middle of the GrabCAD screen, and you’ll see the hole-size immediately changed (larger or smaller as needed). The new diameter will match the required oversized dimensions for the correct (melted into place) part-fit. You can even do this in a sidewall! (For tips on putting inserts into FDM parts, particularly with a soldering iron, see Adding Inserts to 3D Printed Parts: Hardware Tips.)

Note that this way, you can print the overall part with a sparse infill, yet reinforce the area around the insert to create just the right mass to make a solid connection.

Manufacturing notes automatically created in GrabCAD Print when insert holes are resized. Image PADT.

Manufacturing notes automatically created in GrabCAD Print when insert holes are resized. Image PADT.
Sliced view showing insert holes with reinforced walls, done in GrabCAD Print. Image PADT.

Sliced view showing insert holes with reinforced walls, done in GrabCAD Print. Image PADT.

To document the selected choices for whoever will be doing the insert assembly, GrabCAD also generates a numbered, manufacturing-footnote that lists each insert’s size; this information can be exported as a PDF file that includes a separate close-up image of each insert’s location.

GrabCAD Print keeps adding very useful functions. Download it for free and try it out with template versions of the various Stratasys 3D printers, then email or call us to learn more.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

GrabCAD Print Software: Part One, an Introduction

Where are you on your New Year’s resolutions? They often include words such as “simplify,” “organize” and “streamline.” They can be timely reminders to rethink how you do things in both your personal and professional lives, so why not rethink the software you use in 3D Printing?

Preparing a CAD solid model or an STL file to print on a 3D printer requires using set-up software that is typically unique to each printer’s manufacturer. For Flashforge equipment, you use FlashPrint, for Makerbot systems you use MakerBot Print, for Formlabs printers you use PreForm, and so on.

GrabCAD Print software for setting up STL or CAD files to print on Stratasys 3D printers (main screen).
GrabCAD Print software for setting up STL or CAD files to print on Stratasys 3D printers (main screen). Image courtesy PADT.

For printers from industrial 3D printing company Stratasys, the go-to software is GrabCAD Print (along with GrabCAD Print Mobile), developed for setting up both fused deposition modeling (FDM) and PolyJet technologies in new and efficient ways. Often just called GrabCAD, this versatile software package lets you organize and control prints assigned to one of more than 30 printer models, so the steps you learn for one printer transfer directly over to working with other models.

If you’ve previously used Stratasys Catalyst (on Dimension and uPrint printers), you’ll find similarities with GrabCAD, as well as some enhanced functionality. If you’re accustomed to the fine details of Stratasys Insight, you’ll see that GrabCAD provides similar capabilities in a streamlined interface, plus powerful new features made possible only by the direct import of native CAD files.  Additionally, you can access Insight within GrabCAD, combining the best of both traditional and next-generation possibilities.

Simple by Default, Powerful by Choice

GrabCAD lets users select simplified default settings throughout, with more sophisticated options available at every turn. Here are the general steps for print-file preparation, done on your desktop, laptop or mobile device:

1 – Add Models: Click-and-drag files or open them from File Explorer. All standard CAD formats are supported, including SolidWorks, Autodesk, Siemens and PTC, as well as STL. You can also bring in assemblies of parts and multi-body models, choosing whether to print them assembled or not. (Later we’ll also talk about what you can do with a CAD file that you can’t do with an STL.)

2 – Select Printer: Choose from a drop-down menu to find whatever printer(s) is networked to your computer. You can also experiment using templates for printers you don’t yet own, in order to compare build volumes and print times.

3 – Orient/Rotate/Scale Model: Icons along the right panel guide you through placing your model or models on the build platform, letting you rotate them around each axis, choose a face to orient as desired, and scale the part up or down. You can also right-click to copy and paste multiple models, then edit each one separately, move them around, and delete them as desired.

4 – Tray Settings: This icon leads to the menu with choices such as available materials, slice height options, build style (normal or draft), and more; always targeted to the selected printer. These choices apply to all the parts on the tray or build sheet.

5 – Model Settings: Here’s where you choose infill style, infill density (via slider bar), infill angle, and body thickness (also known as shell thickness) per part. Each part can have different choices.

6 – Support Settings: These all have defaults, so you don’t even have to consider them if you don’t have special needs (but it’s where, for example, you would change the self-supporting angle).

7 – Show Slice Preview: Clicking this icon slices the model and gives you the choice to view layers/tool paths individually, watch a video animation, or even set a Z-height pause if you plan on changing filament color or adding embedded hardware.

8 – Print: You’re ready to hit the Print button, sending the prepared file to the printer’s queue.

Scheduling Your Print, and Tracking Print Progress

A clock-like icon on the left-side GrabCAD panel (the second one down, or third if you’ve activated Advanced FDM features) switches the view to the Scheduler. In this mode, you can see a day/time tracking bar for every printer on the network. All prints are queued in the order sent, and the visuals make it easy to see when one will finish and another start (assuming human intervention for machine set-up and part removal, of course).

Scheduling panel in GrabCAD Print, showing status of files printing on multiple 3D printers.
Scheduling panel in GrabCAD Print, showing status of files printing on multiple 3D printers. Image courtesy PADT.

If you click on the bar representing a part being built, a new panel slides in from the right with detailed information about material type, support type, start time, expected finish time and total material used (cubic inches or grams). For printers with an on-board camera, you can even get an updated snapshot of the part as it’s building in the chamber.

Below the Scheduler icon is the History button. This is a great tool for creating weekly, monthly or yearly reports of printer run-time and material consumption, again for each printer on the network. Within a given build, you’ll even see the files names of the individual parts within that job.

Separately, if you’re not operating the software offline (an option that some companies require), you can enable GrabCAD Print Reports. This function generates detailed graphs and summaries covering printer utilization and overall material use across multiple printers and time periods – very powerful information for groups that need to track efficiencies and expenditures.

And That’s Just the Beginning

Once you decide to experiment with these settings, you begin to see the power of GrabCAD Print for FDM systems. We haven’t even touched on the automated repairs for STL files, PolyJet’s possibilities for colors, transparency and blended materials, or the options for setting up a CAD model so that sub-sections print with different properties.

For example, you’ll see how planning ahead allows you to bring in a multi-body CAD model and have GrabCAD identify and reinforce some areas at full density, while changing the infill pattern, layout, and density in other regions. GrabCAD recognizes actual CAD bodies and faces, letting you make build-modifications that previously would have required layer-by-layer slice editing, or couldn’t have been done at all.

Stay tuned for our next blog post, GrabCAD Print Software, Part Two: Simplify Set-ups, Save Time, and Do Cool Stuff You Hadn’t Even Considered, and reach out to us to learn more about downloading and using GrabCAD Print.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and materials, contact us at info@padtinc.com.