From rLab

Some of the tools at the Hackspace are potentially hazardous to use, for these tools members are required to have an induction before they can use them. Inductions provide the most basic information on how to safely and effectively use the simpler functions of the tools, we appreciate that some members may have professional experience on some of these tools and in this case please tell your induction provider and the induction may be very reduced and just cover any risks or procedures specific to rLab. Some tools have multiple levels of induction in order to cover more advanced uses of that tool without making the basic induction take too long, higher induction levels will introduce some of the more advanced features of the tools but as with all inductions are only intended to provide basic information on the capabilities of the tools and how to use them safely. Some members of rLab may be willing to offer more detailed tuition beyond basic induction level or offer guided practice sessions in exchange for beer money or assistance on their own projects.

For all tools you are only required to take level-1 induction before use, after that you may perform any task that you feel confident you can do safely, higher levels of induction may be useful to you in performing more advanced operations but are not required before doing tasks covered in them so long as you're confident of your ability to handle those tasks without risk to yourself, others, or the tool.

PLEASE NOTE : All induction providers are volunteers who are providing inductions to the best of their ability but are NOT qualified instructors. Inductions are provided on a best-effort basis but you and you alone are responsible for your safety while using the tools and for satisfying yourself that you can operate the tools safely. There are professional training courses available from various providers in Reading and the surrounding area if you feel they are appropriate for the level of work you intend to undertake. Reading these notes is NOT a substitute for an in-person induction.

Note for wiki editors : Please do not edit induction pages unless you are one of of the people that gives that induction


The Ultimaker is a FDM / FFF 3d printer. We have two of them which are typically set up with different nozzle sizes (but always check). A variety of thermoplastic materials can be used.

For the induction we will suggest/provide a suitable 3D model but the induction will touch on how to obtain or create 3D models.

Topic Detailed contents Rationale
Overview of process
  • Types of file
    • STLs are most common but don't include size or material data so that's often assumed, not always correctly
    • 3MF is being pushed by Microsoft and does have some advantages by including size and material settings
    • OBJ is an option that's used industrially
  • Modelling files
    • Common software in use at lab - Fusion360, OpenSCAD, FreeCAD, Meshmixer, Sculptress
    • We won't cover how to make files during this induction but there are members who can help you with these packages
    • When designing you have to consider how it will be printed, good design can save many hours of print time
  • Where to get files
    • Thingiverse, Cults3D, scan-the-world etc
      • Watch out for untested files, if you don't see an example print, the file may be un-printable
    • People often publish files on their own sites
  • Slicing in Cura
    • Object files have to be converted into 3D printer instructions
    • The software does this layer-by-layer (hence "Slicing")
    • There are many settings (thousands) but for 99% of them the defaults are fine
    • People often leave weird settings loaded, so it's wise to re-set to default when you start
  • Copying gcode to media
    • The PCs have SD card readers or use your own
  • Power on
  • Inserting appropriate filament, filament settings
    • Ultimaker's filament settings over-ride Cura's
  • Starting print
    • Warmup process
    • Makes a worm cast, then a brim or skit
    • Watch first few layers, if the first layer is bad then abort the print, if the first layers are good then it's likely the whole print will work
  • Monitoring print
    • These printers are allowed to run un-attended but please check the first few layers, and write on the expected completion time
  • Materials costs, how to calculate how much material is likely to be used, how to pay for Rlab materials
  • Handling failures, types of failure
    • Birdsnest - Just clean it up and try again
    • "The Blob" - Call for help from maintainers, it's not a disaster but does have to be correctly handled
  • Remove print, cleanup, recycling PLA etc
Basic process of 3D printing and topics that won't be covered in more detail later
Capabilities and limitations
  • Maximum printing volume
    • 220mm square
    • Trade offs that occur between size of object and printing time
  • Resolution / layer height
    • 0.1mm horizontal resolution, 0.06 minimum layer height, 0.3mm maximum with the 0.6 nozzle
    • Trade offs between resolution and print time
  • Heaters / temperatures
    • Bed up to 110C, but over 90C takes a very long time to pre-heat
    • Head up to 260C, but 250C is recommended as a maximum, going right up to 260C risks an over-heat cut-out from the controller
    • Choice depends mostly on filament type but also to a degree on geometry
  • Overhangs
    • Maximum angle is around 60 degrees, but less prints easier
  • Indirect drive system for filament
    • Indirect drive works with all rigid filaments and most semi-flex, but not with fully-flexible low-shore-A types
  • Nozzle types
    • We leave them fitted with 0.4mm and 0.6mm Ruby-cored nozzles which can handle even highly abrasive filaments such as stone/metal filled, carbon-fibre reinforced or glass-fibre based
    • Finer and Coarser nozzles are available, ask a maintainer if you wish to use them
Description of what the tool can and cannot safely do.
  • Bed
  • X,Y,Z axes
  • Filament, extruder, hot-end, bowden-tube
Common terms that you need to know
Slicing in Cura
  • There are so many settings, we don't cover many, only the ones required to make the print work
  • It's wise to reset the slicer before using and people leave all sorts of weird settings selected depending what they're doing
  • Most important: Nozzle size - if it's wrong then massive under/overextrusion happens. Our printers often have different size nozzles, so decide which you want, and make sure it's set correctly.
  • Select filament type as it affects some other settings but be aware the printer will use it's own temperature, feed and retracting settings and ignore Cura
  • Orientation of workpiece on the print bed - if there is a flat side, you probably want it on the bed. Also check for overhangs and bridging etc, if part cannot be printed in any orientation without support material then you'll have to enable support material or divide it into parts
  • Layer height
    • 0.06mm is the minimum for these printers and you normally don't want that fine
    • 25% of nozzle diameter is a fine print
    • 33% of nozzle diameter is normal
    • 50% of nozzle diameter is very coarse
    • >50% is likely to fail
  • Walls, Top&Bottom
    • Usually measured in multiple of nozzle diameter
    • More walls make an item MUCH stronger, at the cost of longer print time and more filament
    • Walls can be as thin as 1x diameter, but the infill will show through
    • Walls over 2mm thick are seldom needed
  • Infill
    • For aesthetic objects infill is only require to support the top surfaces, very little is needed
    • For mechanical parts, walls add strength more efficiently than infill
    • <8% - Do you really need infill at all?
    • 8%-15% - Light infill, normal for aesthetic parts
    • 15%-25% - Medium structural infill, normal for mechanical parts
    • 25%-35% - Strong structural infill, 35% infill gives about 75% of the maximum possible strength
    • 50% - Extreme structural infill, has more than 90% of the maximum possible strength almost never needed, better to redesign part to avoid needing this
    • 75% - Maximally strong infill, basically never needed, takes forever, costs a fortune, you've designed your part wrong
    • >75% - You're wasting time and money, it doesn't get any stronger above 75% no matter what you do
  • Support material - if required, or not.
    • Best avoided if can, think if you can change the design to remove the need
    • But if you have to use it then it makes clean-up annoying
  • Bed adhesion settings
    • Skirt is normal
    • Brim is for high-aspect ratio parts or very small parts
    • Raft is not needed with this printer
  • Estimated filament weight (to calculate payment if using Rlab material) and print time (for scheduling)
    • Very long duration prints (up to multiple days) are allowed but please be considerate
    • Don't use both printers at once for long prints
    • If you know that you're going to be doing a multiple-day print, please post to the list to warn others in advance
  • Saving file to removable media
Correct slicing will make the difference between a nice print and a waste of 10's of hours and hundreds of gramms
Setting up
  • Check machine is not out of order, look for any sign on it, check wiki
  • Check enough filament, changing spool half-way through a print is possible but you'll need to make sure a second is available and time it right
  • Power on, wait for boot
  • Change filament if necessary
    • Go to menu and select change filament
    • Nozzle will warm up, purge and then back out the filament
    • Remove filament from the back of the printer, coil neatly and secure
    • Confirm on the control panel that filament has been removed
    • Select new filament type, important to pick the right one as the printer will use this to choose settings
      • Compatible filaments are : PLA, ABS, PET, PETg, HIPS, TPU, PVA, PVB, Nylon, PC - Some others are possible, check with maintainers
      • Settings for this filament can be changed from the ?? menu, and such changed will persist till the next filament change
      • Changes like this only recommended when using abnormal filaments, for one-off changes use tune menu when printing instead
    • Insert filament into gromet hole in the driver, confirm it's grabbed it, route the filament correctly
    • Confirm insertion on control panel, printer will advance the filament and then purge till the old filament is fully cleared
    • Confirm on the control panel that purge is complete
  • Gluing the bed if necessary
    • Might be needed for small objects, tall objects, or large flat areas that tend to curl at the edges
    • Use only the supplied PritStick, other glues have erratic results
    • Will result in poorer bottom-layer finish but more reliable prints
    • Glue can be removed with window cleaner spray and blur roll, do not use regular cleaning wipes
Process to get a print going
  • Start print
    • Select file, it'll usually be the last one
    • Do not remove SD card while printing, the printer will crash!
    • Wait for bed heat, then head heat
    • You can use the tune menu to make one-time adjustments to settings, but be aware print will not begin until you leave the tune menu
    • Will extrude "worm cast" then move to start position and begin printing
    • Watch first layer carefully, if the first layer isn't working well then it won't get better, abort and resolve the issue
    • Tune menu can be used during printing
    • You can use pause menu to change filament mid-print if needed
    • Time displayed on the screen is nonsense, ignore it and trust Cura
    • Sometimes the interface crashes, your print will continue but you can no-longer control it, and you'll have to power-cycle the machine immediately the print is finished to make it shut down cleanly
  • Check it from time to time while printing, webcam can help
  • Printer CAN be left unattended
    • If leaving unattended, write a note on the board for subsequent users. Someone else might arrive and remove a finished print (or a failed print).
    • Be especially careful about notes if you're using your own filament or an unusual filament, if you don't others might use it
  • Pay for materials, Price per gram as marked on filament, 50p if using own filament
    • Use Cura's weight estimate for standard filaments
    • Unusually dense filaments (metal/stone filled) will be heavier, weigh afterwards if necessary
Checks to make before you walk off and leave the printer
  • Removing thing from bed
    • Ideally allow print to cool fully, it should just come right off the bed
    • If you want to remove sooner watch the screen, it will say when it's safe to remove. Removal before this is possible but can result in a distorted part or chipping of the glass bed
    • Scraper can remove difficult parts
  • Removing support material, recycling PLA
    • Support material can be removed with pliers usually, sometimes a knife is needed but please be careful!
    • Marks left by support material can be smoothed with hot air, sometimes with solvents
    • Some polymers are designed to be solvent smoothed, check datasheets for details, take extreme caution with flammable vapours
    • Any waste, support material, or failed prints that are pure PLA (so not the purge threads from changing between filament types) can be recycled, please place in the marked bin
  • Cleaning machine and bed
    • Clean up loose bits of PLA, vacuum from laser can help
    • Clean bed if it's messy, use glass cleaner that's kept next to the printer
    • Solvents can be used if especially greasy but take great care not to get on the rest of the printer
    • Clean off note board if you used it
    • Unload filament if it's yours, or something unusual. If it's start rLab supplied PLA, leave it loaded
Leaving it in a good state for others