This slicer trick can save you time and money on your 3D prints

You can improve many items with 3D printed upgrades, but things don’t always fit perfectly the first time around. It’s frustrating to spend time and money waiting for an object to print, only to find out it was all for naught and you have to start again.

Thankfully, there’s one nifty little slicer trick that you can use to check the fit before you print the whole thing.

When to use this trick

By slicing out the part of a model that needs to fit precisely, you can print just that part before committing to the whole thing. This could be a section of a model into which something slides (like a case), a replacement part that is designed to slot into a groove (like a fridge shelf), or two parts of the same model that are designed to slot together.

It’s ideal for both items you have designed yourself and those you have downloaded from model repositories. Sometimes a model’s comments will reveal that some people think the model is too loose or too tight. Occasionally, the author will post a 1% scaled model to address these concerns.

On top of this, different filaments behave in unique ways. If you want to print a model using a specific type of filament (like PETG instead of PLA) but you’re not sure if this will result in unexpected shrinkage, printing a fit guide can alleviate your concerns.

Cut, slice, print

You can use this trick with any model that you can import into a slicer—take your STL, OBJ, or 3MF file and open it up. I’ll be using Bambu Studio for this example, but all modern slicers should give you access to a cut tool, which we’ll be using.

Before you slice your model in preparation for print, select the model and find the “Cut” tool. In Bambu Lab, you’ll see a selection which you can manipulate by changing the X, Y, and Z axis angles:

Let’s take an example model of a Mac Mini upright stand, something you don’t want to be too tight or loose. This is a fairly small model that’s light on filament (33g) using the author’s default settings, with a print time of around an hour and a half. I took the cut tool and changed the X axis to 90º, and then positioned the plane to cut the model in two:

Clicking “Perform cut” gives me two pieces. I deleted the larger section of the model and created another cut so that I essentially end up with a cross-section of the model around which the Mac mini is supposed to fit. The last thing to do is reorient the model so that it prints in an identical fashion to how the “real” model will print using the “Lay on Face” tool:

Now to slice the model again and see that I’ve cut the total filament cost down to just under 3g and the print time (including calibration) to around 30 minutes. At this stage, you can even use a different color to your final print (like a spool end you’re trying to finish) provided it’s the same filament type and behaves in the same way as your finished item would.

Damned if you do, damned if you don’t

Once your test print is complete, you can take it off the bed, try the fit, and make any adjustments that are necessary. You could even print a second test print if you aren’t sure.

The obvious downside to working like this is that you’re spending time and filament creating an additional print that you might not need. If your model fits the first time, you’re going to question the validity of this approach. It will seem like you should have just printed the model in one shot, right off the bat.

That’s a valid concern, but consider the alternative. If you sacrifice hundreds of grams of filament and hours of print time producing an item that doesn’t fit correctly, you’ll wish you had acted differently.

Perhaps the best way to use this trick is to do so sparingly, only on prints that feel like a real commitment.

One of the best times to use a trick like this is when you’re using your 3D printer to augment power tools, and the fit needs to be just right.