Fast Instructions for Use "IFU" for Asiga printers

Standard settings for printing 3D resins with Asiga printers:

  • Z layers of 0.050-0.100 mm (lower or higher are also printable)
  • Exposure time for 50-100 microns layers are around 2-20 seconds approximately for most resins
  • Typically, 80 seconds of Burn-In are enough for having good cure and adhesion of most resins on the build platform
  • Depending on the chosen power (7 mW/cm2 are chosen by defect in the DentalMODEL standard settings) of your Asiga printer, the optimum exposure times will increase or decrease. Follow our Instructions for Use in detail. Measure and fill up the data, cure thickness vs exposure time, in the curing rate table for your specific printer specs, such as your chosen printer power.

Printing

Open your Asiga Composer: Click on NEW

  • Choose your exact printer model and Z layer thickness in mm. The most used Z layers are 0.050 mm or 0.100 mm.
  • Use the by defect DentalMODEL material or any other:

Click on ADD PARTS:

Add 3Dresyns 1st calibration files 3Dtest1: the flat coin without any supports

Click on the BUILD WIZARD:

Press NEXT

In the Build wizard use a Base Plate Thickness 0f 0.000 mm since during calibration the flat coin will be printed without any base nor supports. Leave the anti-alising checkbox unclick.

Use 80 seconds for Burn-In exposure time for ensuring adhesion on the build platform

Leave at Zero value: Z and XY compensation

The build wizard by defect as shown above shows 2.5 seconds for the exposure times. This value needs to be replaced by a value obtained after filling up the curing rate table at the power of 7 mW/cm2 by using the spot timer tool in the Asiga printer.

How to choose the optimum exposure times?

It is crucial that the following Curing Rate Table is filled up by you for getting the optimum exposure time of the 3D at your chosen Z layer thickness.

How can you fill up the Curing Rate Table? By measuring the thickness of drops of the resin cured at different exposure times.

Exposure time (seconds)

 Curing Rate Table: Thickness of cured resin (in microns) vs exposure time

Thickness shown below are not real values: take YOUR OWN measurements yourself!

5

Example: 0 microns, uncured

10

Example: 30 microns, soft, too tender, poor adhesion on glass, easy to break: requires more time to cure properly (feel the strength of the cured drop with your fingers and nails)

15

Example: 60 microns, cured, hard, strong, better adhesion and strength

20

Example: 120 microns, well cured, hard, tough, good adhesion and strength

25

Example: 130 microns, well cured, good adhesion

30

Example: 140 microns, well cured, good adhesion

50

Example: 150 microns, well cured, good adhesion on glass.

75

Example: 170 microns, well cured, very good adhesion. Ideal exposure time for printing the first 2 adhesion layers!!

100

Example: 180 microns, over cured, very good adhesion

Calibration steps:

  • Remove the build platform from the printer
  • Apply a drop of the liquid resin on a glass slide on the centre of the vat or resin tank in the printer. Then, cure it for example for 5 seconds
  • Then, remove gently with tissue paper the unreacted liquid resin from the glass slide and measure with precision the thickness of the cured resin with a calliper or micrometre. Feel the mechanical strength of the cured drop and write a comment it on the curing rate table

   

  • Repeat the cure test again with a new drop of resin, position it close to previous one on the same glass slide but with a longer exposure time, for example, 10 seconds, then remove the unreacted liquid resin with a paper, clean it and measure again the thickness of the cured resin. Feel the mechanical strength of the cured drop and write a comment it on the curing rate table
  • Repeat this process with longer exposure times, for example 15, 20, 25, 30, 50, 75, and 100 seconds. You will end up having x cured drops positioned in a row, with different exposure times and thickness. This will be your fingerprint of your 3D resin in your specific printer status

Fill up the Curing Rate Table with the results of your measurements

It is recommended to represent both, short and long exposure times, for example, 2, 5, 10, 15, 20, 25, 30, 50, 75, and 100 seconds. These times can be custom varied if needed to adapt to different printer powers, print speeds and resin systems.

Remember to measure the thickness of each cured drop and evaluate its green state and write a comment about its strength in your notebook or ideally in the same curing rate table.  All 3D resins pass from liquid to solid state, through a green state, in which the resin can be too tender or soft to resist the peeling or separation or lift from the vat or resin tank during printing. Choose long enough exposure times to ensure that the resin has enough mechanical resistance to withstand the separation from the tank during printing. Typically, the optimum exposure time is the time needed to cure in between one and two layers, in this example, the time to cure between 50 and 100 microns, which is approximately around 14 and 18 seconds.

It is recommended to initially start printing the first calibration file 3Dtest1 with the exposure time needed to cure 1.5 layers. Depending on the results, the exposure time can be:

  • Reduced by using the time required to cure between 1.1 and 1.2 layers if the printing was successful, with the goal of increasing print speed, or
  • Increased by using the time required to cure between 1.75 and 2 layers with the goal of increasing printability if at shorter times the printing failed
  • To have good adhesion of the resin on the build platform is important to print a Burn-In layers at long exposure times at around 80 seconds to ensure optimum adhesion on the build platform. Alternatively, more scientifically, use the exposure time at which the resin showed optimum adhesion and cured well on the glass slide. In this example, in 75 seconds the resin cured well and had very good adhesion on the glass slide (see example on the Curing Rate Table above), so use this time for curing the first two adhesion layers. Once the exposure times have been chosen, then the next step is:

Start printing 3DTest1: the flat coin without any supports, using 80 seconds as Burn-In time (as already explained) and for standard layers use initially the exposure time needed for curing 1.5 layers: this value is the time needed  to cure 0.075 mm considering your chosen z layer thickness is 0.05 mm! Write this exposure time value in the exposure time row and 1 column cross: where the 2.5 seconds by defect is positioned.

  • Printing the coin flat with the standard size as supplied is ideal for evaluating the printability and xy resolution
  • The flat coin is printed without supports directly on the build platform. This first calibration test helps to identify the printability of a 2 mm thick coin of 25 mm of diameter, which can be printed for example with 20 z layers of 0.1 mm or with 40 z layers of 0.05 mm. This fast calibration file consumes very little resin and provides a proof of printability with the chosen settings, as well as an indication of xy resolution since each concentric circle has certain width and depth
  • The first concentric line starts with a width and depth of 500 microns (0.5 mm), the following ones have 400, 300, 200,150, 100, 80, 60, 40, 20, 10, 5, and 2 microns
  • This fast calibration tests gives an indication of the xy resolution, since the thinnest observed circle will determine the xy resolution of the resin with the chosen printing settings

  • It there is any printing failure, reflected because the coin is not fully printed, it is crucial to determine at which stage the printing failed:
    • If the whole coin separated from the build platform the bottom exposure time (and the number of bottom layers) needs to be increased to promote the adhesion of the resin to the build platform
    • If part of the coin was printed and another part remained adhered to the build platform the normal exposure time needs to be increased or decreased:
      • Increase the exposure time several seconds in case the printed part left on the build platform is too tender: under cured
      • Decrease the exposure time several seconds in case the printed part left on the build platform is too brittle: over cured
      • Once you find the right exposure times for printing 3Dtest1 well, then you can use them for printing 3Dtest2: the flat coin with supports shown below:

Print 3DTest2: the flat coin with supports

  • Once the flat coin is printed without defects you may print 3Dtest2, the flat coin with supports. This second calibration file provides proof of printability of the coin with supports with the optimised settings used for printing the wedge or the flat coin without any supports, as well as an indication of xyz resolution, since depending on the obtained printed thickness of the coin, the z resolution will be higher or lower. If for example, the thickness of the printed coin after removing the supports would be 2.1 mm, knowing that the theoretical thickness is 2.0 mm, the accuracy would be =(2.1-2.0)x100/2=5 % z accuracy
  • The tips or connections of the supports to the coin are deliberately quite thin to permit printing structures with minimum supports, or with minimum tip sizes, to reduce the marking of the connections on the surface of prints

Evaluation the quality of the printed coin with supports

  • Evaluate the xy resolution as shown before by reading the smallest width and depth of the printed concentric circles
  • Measure the thickness of the coin vs the theoretical 3Dtest1 thickness, which as supplied has 2.0 mm, to quantify the z axis accuracy. This will permit you to calculate the % relative error in the z axis
  • If you are not fully satisfied with the quality, or detail, or accuracy of your prints it is necessary to fine tune the 3D resin with our Fine Tuners, and/or adjust your printing settings, e.g. by decreasing the exposure time or the light power. Depending on the origin of the print quality problem, different solutions are available.

Basic tools needed for calibration (click on the links to find commercial references):

Cleaning and processing of prints:

General Information:

  • The final physical and mechanical properties of any 3D printed material depend, among other things, on the printer specifications, printing settings, and post processing protocol. Results depend on few variables such as wavelength, power, exposure time, cleansing protocol (chemicals used for cleansing, cleansing time, cleansing temperature, etc) and light post-processing or light box curing (wavelength, power, post curing time, temperature, dry light box post curing, or dipping in our Cleaning Fluid UNW1 Bio, etc).

Consulting

You are welcome to contact us and order more products and services by email at: info@3dresyns.com

Specific calibration instructions IFU for Asiga printers

Remember through this calibration testing process that the objective is to find the best printing settings of your 3D resin in your printer to meet your overall specifications, to say printing speed, or resolution, or biocompatibility.

All prints (3DTest 1 and 2) require no extra supports – position them straight on the build plate. Please read this document to help you understand the objectives of the calibration test prints.

Most 3D printed materials benefit from a gentile post cure exposure to UV/Visible light, which significantly improves the degree of cure of the printed resins and consequently their safety and biocompatibility. Most of our resins may be used directly as printed but will exhibit even better properties after post curing for around 5-60 minutes in any conventional commercial light box. Excessive light power, time, and temperature during post curing above 60ºC can cause yellowing to some materials.

Our resins are designed to cure with UV/Visible light from 250 to 420 nm and different light powers, from the very low power typical of LCD printers, to the high power of the new generation of SLA lasers and DLP projectors. Asiga printers permit choosing your light power for each sold wavelength 385 and 405 nm.

The calibration process for Asiga starts with selecting the optimum light power and printing temperature. The higher the temperature, the lower the viscosity, the adhesion and peeling force needed to separate the printed layers from the vat. Viscous resins are normally more biocompatible and tougher than lower viscosity ones and can really benefit from printing them at 30-35ºC to increase their flow and reduce their stickiness or adhesion on the vat.

On the other hand, the higher the power the faster the printing speed but the lower the resolution. After choosing the optimum power for your printer specifications, it is necessary to undertake the spot timer test with the following times, to say, for example, 2, 5, 10, 15, 20, 25, 30, 50, 75, and 100 seconds. After measuring the thickness of the drops or spots with a calliper, a curing rate table needs to be drawn including exposure times in seconds, energy dosage in mJoule per cm2, and spot thickness in mm for each exposure time.

Then, select the z layer thickness for printing: typically, 0.05-0.1 mm, which usually give good print resolution. Now, select as exposure time, the time needed to cure in between one and two layers. Use as burn-in exposure time the time needed to get very good adhesion and cure on the glass slide, usually, between 80 and 90 seconds for most 3D resins.

In the Composer, use any INI file as reference. Then in the build wizard, specify your chosen power, exposure time, burn in exposure time, number of burn-in layers, etc. It is suggested to leave at zero the XY and Z compensation values and use the maximum speed values. Other complex values can be ignored or used at their medium point of the interval.

 

3DTest2: the flat coin with supports

This print is the most important; it helps setup and refines the most things as quickly as possible. It will permit us to identify the accuracy of the printed resin in the chosen printer settings. Excessive thickness in xyz planes is normally caused by light bleed. Print failure can be easily overcome by adjusting the exposure time.

Please remember that all printer types will have available certain UV or visible light power at the build surface to cure the resin. This power is measured in mW/cm2. Dependent on the printer design this power can vary greatly and can even vary from one point of the build area to another (non-uniform light power distribution).

This power can be measured using a radiometer that has a sensor in wavelength range of the light source. 

In terms of the best print orientation for high quality printing, this flat print or coin orientation is not ideal, the printing plane orientation (parallel to the build plate) is the worst possible scenario – it is likely to trap liquid resin, which will be overexposed to light and will tend to cure causing bleeding in the z direction, appearing the back of the coin thicker than the theoretical 2.0 mm of the original STL file. Additionally, the tips of the supports are deliberately tiny to simulate print zones with nearly no supports.

All these features are deliberate; they make the print difficult to print. If these test pieces print well then 99.9% of all prints with that resin in the future will be a success. As mentioned before, a good starting point would be to set the exposure times per layer between 1 and 2 layers, to say, the time needed to print 0.075 mm (for printing Z layers of 0.05 mm) in the spot timer test.

Possible printing problems and solutions with 3DTest2 print:

Note: during the following stages do not alter the base or burn in layer exposure time – just the build layer times. You established the base exposure time with the first test print (3DTest1).

Base and first part of supports print but the coin is found separated in the resin vat.

This is caused by possibly one of two reasons; the material is too reactive and brittle, and the supports have snapped off where they join the coin. Or the material is not reactive enough and is curing too soft and the coin has separated.

Use your fingers or a needle and try to press it into the top of the cone or support attached to the base plate. Is the material at the top of the printed cone relatively too soft, or tender, or too hard, or brittle?

  • If it is too soft, or tender, repeat the print after increasing the exposure time and use the time needed to print 2 z layers, or 0.1 mm (100 microns) in the spot timer test, for printing z layers of 0.05 mm (50 microns), and repeat the print
  • If it is too hard/brittle repeat the print after decreasing the exposure time and use the time needed to print between 75 microns in the spot timer test and repeat the print

Continue this process until the print works (it may take several prints).

The coin has printed but the thickness of the coin is much thicker than 2.0 mm

This is caused by light bleeding in the z direction due to excessive light penetration, normally caused by excessive light power or exposure time.

Our 3Dresyns are delivered ready to print with good resolution in a wide range of light powers. In case you want to print at a very high speed at very high power of e.g. 20 mW/cm2, you may end up needing to use our resolution adjuster or resolutioner Fine Tuner LB1 Bio. First, you will need to repeat the calibration after adding Fine Tuner LB1 Bio in steps of 1% (remember to shake it well or warm it up to approximately 70ºC until crystals dissolve completely) until the support legs and the back of the coin are printed correctly with good definition and with the original thickness of 2.0 mm of the coin. Make sure that no light bleed is spoiling the printed circles down to your goal resolution down up to 2 mm, the smallest concentric circle.

It can take time to do these tests, but the result is worth it. You will have the very best physical material properties, accuracy, and printability for a particular resin type on your specific printer settings specifications.

Photopolymeric resins are not like clothes and “One size fits all” does not yield the best results for a range of printers. When you have found the optimum for your type of printer – record your printing settings. In the future you can print using the build wizard or create your own INI file.