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How To Resume a 3D Print After a Power Loss

Sometimes, a power outage interrupts your 3D printing. And when this thing does happen, we’d end up with half-finished models. The good news is that you can resume printing failed 3D models.

Here are the ways you can resume a 3D print after a power loss:

  1. Remove the unfinished print.
  2. Don’t remove the model.

Continue reading about how to resume 3D printing after a power outage after a power loss. We have several ways to save you time, filaments, and effort.

Resuming or Restarting a 3D Printer After a Power Loss

Power interruptions happen, and if you’re in the middle of 3D printing something, that could mean having half-finished models waiting for you. Other times, your printing is interrupted because somebody tripped on the wire and dislodged the plug from the power outlet.

You might also want to manually pause or temporarily stop the printing from changing the filament or replenishing it when it runs out. Whatever the reason, having an interrupted printing process can leave you with an unfinished model just sitting there on the heat bed. And for the inexperienced, an unfinished 3D object could mean a waste of time, energy, and material.

Some people think there’s no way a 3D printer would resume the job or pick up where it left off after losing power. They just restart or do the printing process all over again from the beginning, wasting all that filament used in the partially printed model. 

However, there are ways to resume printing after a power loss. If your 3D printer has the auto-resume function, it’s not much of a problem. You can just use the feature to continue printing as if nothing happened.

But if you have an older 3D printer or one that doesn’t offer an auto-resume feature, you can still complete the model through these methods.

1. Remove the Unfinished Print

If you have an incomplete model, follow the steps below:

Remove and Measure the Unfinished Model

After the power comes back on, you can remove the unfinished print from the bed. Get a ruler or a caliper to measure the part from the base.

For this step, you might want to invest in a digital caliper that can give you measurements right down to fractions of a millimeter. Here are digital calipers available on Amazon.com that we can recommend:

Unlike a ruler, these digital calipers will give you more precise measurements than you can read on an LCD screen. No more estimates and guesswork.

Split the Print and Resume Printing

Using a slicer program, you can split the print so that your 3D printer only prints the unfinished portion of the model. On the slicer, you can cut off as many of the parts that you’ve already printed.

Resume printing the unfinished portion and just wait for it to finish the job.

Sand and Bond the Models Together

Wait for the second half of the print to finish. Once it’s done, you can remove it from the heated bed. Then, sand both halves of the model and glue them together. 

Super Glue

Now you might ask, which glue products should you use. Here are our recommendations.

For rigid filaments, you can use super glue. Here are products available on Amazon.com that dry in seconds and produce a thin layer that bonds the two plastic pieces together without any visible seams:

However, it would help if you used super glue when you’re using flexible filaments. The elastic materials can easily break the rigid layer that the glue creates, and, in turn, this could break your model.

3D Pens

Aside from using super glue, you might want to consider investing in a 3D pen. These products can use the same filaments that you’re using for your models. 

As a result, when you glue the two parts together, it’ll look like it’s been printed as one. Here are our recommendations that are available on Amazon.com:

  • 3Doodler 3D Printing PenIt allows you to create 3D doodles in a matter of minutes.
  • MYNT3D 3D Printing PenIt has an adjustable flow so that you can control it better, making it ideal for smaller parts. 
  • SCRIB3D 3D Printing Pen: It gives you the option to get 10 filaments of different colors, ensuring that you can glue together the two halves using a similar colored filament.
Other Things You Can Use To Bond the Two 3D Printed Parts 

So if you don’t like using superglue and you see no need to invest in a 3D pen, there are some other materials that you can use to bond two 3D printed pieces together:

  • Acetone. You can use acetone for ABS and HIPS as these materials are soluble in acetone. Go ahead and apply a thin layer of acetone on both parts, and then stick them together.
  • Plumber’s cement. This material works like acetone in that it can dissolve a bit of your 3D prints so you can bond them together. Plumber cement works best with ABS, HIPS, PLA, and PETG filaments.
  • Epoxy. Like glue, epoxy can be used for bonding 3D prints. But because they form a hard layer, it’s also not a good idea to use epoxy for flexible filaments.
  • Hot glue gun. If you’re working with PLA filaments, hot glue guns are your best bet for bonding two pieces together.

2. Don’t Remove the Model

If your 3D model is still on the printer bed, follow the steps below:

Clean the Last Layer That Was Printed

Very gently, you should clean the last layer printed before the power is cut off. Remove the imperfections on the unfinished model, and that includes clearing out the leftover material.

You should also be on the lookout for those areas that weren’t printed properly. Remove the dried threads of filament and even support materials.

Measure the Height Where the Printing Failed

Here are several ways that you can get an accurate height on your failed models:

  • Using calipers or a ruler, you can measure the height of the failed print from the base.
  • Look at the geometrical features. Open the G-code for your model and look at the geometrical features and sections where the print failed.
  • Use your 3D printer. You can also move your 3D printer’s nozzle so that it touches the last layer printed. Look at the height on your 3D printer’s screen.

After you get the height where the printing failed, it’s time for you to figure out at which point you’d want your 3D printer to resume printing. There are two schools of thought on this.

  • The first is to continue printing at the exact layer height where the printing failed. So if your 3D printer stopped printing at 80 millimeters (3.15 in), you should resume printing at that height.
  • Others recommend resuming your prints at the next layer. To do this, you’ll need to consider the print layer’s resolution. If you’re printing your models with layers of 0.1 millimeter (0.004 in), then you should add that to the 80 millimeters (3.15 in) of your failed prints.

Modify the G-Code

Removing the half-printed part from the heated bed, you can measure it from the base. Taking note of those measurements, you’ll need to edit the G-code for that particular model to start at the point where the printing process was interrupted.

The G-code is a programming language that allows you to tell your 3D printer what to do. This code will know where to send the extruder, how fast it should move, and what path it should take.

A G-code is very easy to read, so don’t be intimidated by all those letters and numbers. Commands have the same structure: G# X# Y# Z# F#

The G# will tell your 3D printer to do a specific action. For instance, G1 will instruct your 3D printer to move to a specific position, which is the coordinates listed in X#, Y#, Z#. The F# represents the feed rate, or how fast the movement will be.

What’s important in the process of resuming your prints is the value for Z. So, let’s say that the unfinished print is 0.63 inches (16 mm) tall, you’ll need to start printing at the 16-millimeter (0.63 in) mark if your layer height is 0.1 millimeters (0.004 in).

Search the G-code for Z16 and delete every G-code before that. Load the new G-code and resume printing. 

Resume the Print

Once you’ve loaded the new G-code, you’re ready to start printing again. Your 3D printer will just pick up where it left off and finish the model for you.

This particular method is good for unfinished models that are still stuck on the printer bed and when you can send the Z-axis home. That means sending the Z-axis to zero coordinates. 

What To Do if the Z-Axis Can’t Be Homed

There are times when the z-axis can’t be homed. Maybe the failed print is blocking the homing movement, or it can be because of other reasons. If that’s the case, then you should edit the G-code and look for the G28 command.

The G28 command tells your 3D printer to send the X, Y, and Z axes to zero coordinates. If you can’t send any of the axes home because the failed print blocks it, you can just delete any line in your G-code with G28.

Avoiding Having To Resume Printing

As you can see, having a 3D print interrupted can be quite cumbersome and involves extra steps that can waste time and effort. One good way of avoiding this is to buy a 3D printer that has the auto-resume function.

You can just turn them back on in these printers, and a message will ask you if you want to resume printing after a power outage. In some printers, this message appears when you power your 3D printer back on. 

On others, it’s not so straightforward. For example, with the Creality Ender 3, you might need to initialize the SD card to continue printing.

Watch this YouTube video to know just how that works:

Getting a UPS

If you don’t like to change your 3D printer now, you can at least invest in an uninterruptible power supply that can keep it going in the event of power cuts or fluctuations. Here are some of my recommendations that are available on Amazon.com:

CyberPower UPS System 

This IPS System allows you to keep your 3D printer running for a few minutes when the power cuts out. This will give you enough time to pause your print and check the coordinates of your prints.

This way, you no longer have to measure the print manually. This UPS is also great for momentary power outages that last no longer than 4.5 minutes at full load or 15.5 minutes at half load.

Let’s say the power goes out just for a minute. Your 3D printer can continue its job without any interruptions.

APC UPS

This UPS works just like other UPS in that it gives your 3D printer electricity when you accidentally unplug it. At 100 watts, this UPS can have your 3D printer running for another hour or so.

What’s more, you can use this to protect other appliances, computers, and devices from power surges.

Jackery Solar Generator

This solar generator doesn’t only keep your 3D printer powered even during an outage, but it harnesses energy from the sun to keep it going indefinitely.

So if you’re in an area that gets a lot of power interruptions, getting the Jackery Solar Generator can save you a lot of time and effort in ensuring that your 3D printer is properly powered.

Final Words

Power interruptions are a normal part of life. If your 3D printing is disrupted by a power outage or by a clumsy co-worker tripping on the cables, you don’t have to start printing over again. You can just follow the steps we’ve outlined here and save time and filament to finish what’s already printed.