After going through the effort of slicing and loading your 3D model, nothing’s more frustrating than seeing the printed material not stick to the print bed. You watch helplessly as your print tugs, curls and eventually pops off the build plate, resulting in spaghetti-like strands or a fallen over mess.
Poor bed adhesion is one of the most common issues that plague 3D printing, particularly when using popular materials like PLA. Thankfully, there are several ways you can promote better print adhesion so you don’t have to deal with the headache of failed prints.
Common Causes of PLA Not Sticking to the Print Bed
Before we get into solutions, let’s look at some of the typical culprits behind PLA not adhering to print beds:
Improper Bed Leveling – If the nozzle is too far from or too close to the build surface, you won’t get a “squish” that smashes the first layer firmly down. Re-level the bed and adjust Z-offset for consistent squish.
Dirty, Greasy or Coated Build Surface – Any contaminants on the print bed can severely affect print adhesion. Clean the bed with isopropyl alcohol to remove oils, grease and residue.
Cold Print Bed – PLA needs heat to stick. Print beds below 50°C won’t provide enough thermal energy for adhesion. Raise the temp to 60°C.
Cooling Fans On Too Soon – Strong cooling fans can rapidly shrink and curl the edges of a print before it grabs the bed. Slow them down for the first few layers.
Incorrect Bed Material – Some build plates stick better with PLA than others. PEI, BuildTak and blue tape work great. Glass and acrylic may struggle.
Drafts or Ambient Temperature Too Low – Air currents and environments below 20°C can quickly cool prints enough to detach from the bed. Shield from drafts and use an enclosure.
Print Speed Too Fast – Going too quickly, especially on the first layer, reduces adhesion as it doesn’t give the plastic time to grab. Slow things down.
Filament Wetness – Absorbed moisture in filament creates popped bubbles and bonding issues. Dry filament prior to printing.
No Brim or Raft – Larger surface area from a brim or raft prevents corners from lifting. Use them for small part footprints.
With the common problems identified, let’s look at the top solutions and best practices to get flawless first layer adhesion when printing PLA.
Bed Leveling and Nozzle Height
Proper bed leveling sets the foundation (literally) for getting prints to stick by ensuring your nozzle is the ideal height over the build plate. The general goal is to get the first extruded filament lines squished into the print surface while still expanding outward.
Use the paper method, feeler gauges or bed leveling sensors to get the proper clearance. For PLA, start with a 0.1mm feeler gauge or regular copy paper with a slight friction drag. From there, fine tune with live adjustments during the first layer.
Many printers also have Z-offset controls that let you dial in small changes to the nozzle height while printing the first layer. Watch the extrusion and adjust Z-offset until you get proper squish and flattening of the lines without plowing into the surface.
Getting the nozzle height right takes trial and error, but it’s crucial for getting those first lines adhered firmly to the print bed. Take your time leveling the bed and tuning Z-offset. It will save you endless headaches down the road.
Cleaning and Prepping the Print Bed
An often overlooked step is making sure your print bed or surface is clean before printing. Any oils, contaminants or leftover plastic from previous prints can severely reduce bed adhesion.
For build surfaces like PEI spring steel sheets or flexible plates, wipe them down with 90% isopropyl alcohol to clean. Give the alcohol a minute to flash off before printing.
On glass print beds, clean thoroughly with soap and water first, then use isopropyl alcohol between prints. Adhesion promotors like gluesticks, hairspray or adhesion sprays can also be applied to glass prior to printing.
If using blue painter’s tape, replace it whenever the top gets dirty or plastic builds up on it. New blue tape provides much better adhesion than old, greasy layers.
Proper print bed cleaning and prep work goes a long way towards getting your first layer to grab hold rather than slide around. Don’t skip this step!
Heated Beds and Enclosures
For PLA prints, you want your print bed temperature between 60-70°C. PLA needs thermal energy to soften and adhere firmly. Beds below 50°C often don’t provide enough heat.
Turn your bed up to 60°C and let it fully preheat before printing. If you still have adhesion issues, incrementally increase the temp in 5 degree increments up to 70°C maximum.
Enclosing the printer also keeps ambient temperatures warmer so cold drafts don’t peel up print edges. DIY enclosures can be made from cardboard or foam boards.
Heated chambers take things a step further by heating the air around the printer. They provide the ultimate environment for keeping large PLA prints stuck firmly to the bed. An enclosure or chamber is a worthy upgrade if you print large, delicate PLA parts.
Cooling Fan Settings
Part cooling fans are great for improving PLA print quality, but too much airflow too soon can cause corners to lift and prints to detach.
For the first layer or two, reduce your cooling fans to 0-30% maximum. Allow the initial layers time to grab onto the bed before hitting them with high airflow. Slowing the cooling fans gives the print time to anchor itself.
Curling corners are also a sign that the fans kicked on too soon. Increase the layer height at which fans go to 100% to reduce major air blasting of the first few layers.
Dialing back the cooling fans at the start of a print avoids rapid shrinking and curling that can pry those first solid lines off the print bed.
Optimal Print Bed Surfaces
The composition of your print bed surface plays a major role in PLA adhesion. Some materials stick like glue while others struggle to grab plastic.
PEI spring steel sheets are regarded as the gold standard for PLA bed adhesion. Their textured PEI coating bonds tenaciously with PLA plastic. Plus, they pop off prints when cooled for easy part removal.
Other strong contenders are BuildTak print surfaces, powder coated PEI rigid plates, and blue painter’s tape. These all provide great adhesion when properly prepped and cleaned.
On the other side, bare glass and acrylic sheets perform poorly with PLA. Their ultra smooth surfaces don’t give plastic much to mechanically adhere to. Kapton tape sheets also don’t grip well.
If your current bed surface constantly struggles with adhesion, try a different material known to work better with PLA like PEI or BuildTak. It’s an easy upgrade that can save lots of headache.
Ambient Temperature and Drafts
Cool ambient air can quickly solidify extruded plastic before it bonds to the bed. Make sure the room you’re printing in is at least 20°C or higher.
Drafts from HVAC vents, open doors or windows can also wreak havoc on prints. Fast moving air currents peel up corner edges once they cool and shrink.
Block air ducts that direct cold air onto the printer. Close doors and windows to seal out drafts. An enclosure around the printer also provides a stable air envelope.
If adhesion still falters, a heated chamber takes things a step further by actively heating the air during printing. This keeps ambient temperatures warm and draft-free for maximum stick.
Slowing Print Speeds
Flying around the print bed at 50+ mm/s sounds exciting, but it doesn’t do your first layer any favors. Slow things down to 30 mm/s or less for better adhesion.
Slower print speeds give the plastic more time to bond with the bed before the next line is laid down beside it. The extra milliseconds make a big difference at the start.
For tricky filament colors or exotic materials like wood or metal filled PLA, drop first layer speeds down to 20 mm/s. The slower extrusion lets it grab and anchor better.
Don’t be in a rush – take things slowly for the first few passes. You can speed back up for higher layers once the print establishes itself on the bed.
Drying Filament
Exposed to humidity, PLA will absorb a small percentage of moisture from the air. This causes sizzling and bubbling from the nozzle as water boils out.
Wet filament struggles to bond to print beds. The escaping moisture prevents the extrusion from properly grabbing the bed.
Pull filament straight from vacuum sealed bags and print immediately if you live in a humid climate. For opened spools, dry filament for 4-6 hours at 50°C before use.
Dryers for 3D printing filament are available, but box food dehydrators also work extremely well for drying wet plastic.
Don’t underestimate the importance of filament moisture control. Many bed adhesion issues disappear when using properly dried material.
Brim and Raft Settings
If all else fails, increasing the surface contact area with a brim or raft will surely get your print to stick.
A brim extends the footprint a few millimeters around the base of the print, giving it more surface area to grab onto. Adjust your slicer settings to add a 5-10mm brim.
Rafts build a floating base layer underneath the print that acts like a sticky scaffold to support it. Enable a raft in your slicer, adjusting the overlap and spacing to get a solid base.
Brims and rafts use more material, so remove them once the print finishes. But they are invaluable tools for small part bed adhesion without other major surface prep.
Dial In Your Bed Adhesion Settings
Getting consistently stellar first layer adhesion with PLA is very achievable, but it requires dialing in the right settings for your specific setup. Variable factors like print bed material, nozzle size and ambient conditions mean no two printers print the same.
Don’t be afraid to experiment with bed leveling, nozzle height, fan speeds, bed temperature and print speeds to find the adhesion sweet spot. Take notes on what works well or fails miserably.
With some trial and error, you’ll learn the ideal combo of settings for your printer. Achieving that perfect first layer squish, stick and appearance is extremely satisfying.
Once you unlock great bed adhesion, filament type almost becomes irrelevant since you can stick it all down firmly and reliably. Spending the time to optimize adhesion now saves endless headaches down the road.
So grab your toolkit, fire up the printer, and let’s get tinkering! With this guide’s tips and tricks, you’ll gain the bed adhesion mastery needed to 3D print like a pro.
