Printing Guidelines: Tuning our 3Dresyns in SLA, DLP & LCD 3D printers
3D Printing and Fine tuning basics
Original and non original commercial 3D resins usually experience print quality variations depending on different printer settings, print specifications and printing variables, such as light power, wavelength, exposure time per layer, z layer thickness, print size, shape, angle or slope, etc.
For example, even with the same SLA, DLP & LCD 3D printer, any 3D resin that gives relatively good quality prints at a specific layer thickness may suffer basic quality printing problems when printing at higher or lower layer thickness or even by simply changing the angle or slope of the print.
The optimum print quality for each 3D resin can be fast and easily achieved by increasing or decreasing the dosage of our Fine Tuners, the power and/or the exposure time for certain z layer thickness (if your specific printer permits it).
Most commercial SLA, DLP & LCD 3D printer manufacturers have significantly limited the opportunity of printer users to adjust printing settings and resolve basic print problems, allowing most of them just to change the layer thickness, the supports density and their size (closed mode, black box system).
In practice even at their optimum printing settings, most commercial 3D resins are often too brittle or fragile. Our 3D resins and Fine Tuners have been designed to help you to overcome these limitations.
All 3D resins need adjusting, fine tuning, to different printer settings
Our Fine Tuners give the opportunity to printer users to resolve any basic and common print quality problems.
In fact, to obtain high quality results (maximum resolution and detail) at different printer settings all 3D resins and printing variables can be fine tuned by either fine tuning the printer settings: adjusting the power and the exposure time if the printer permits it, and/or just by fine tuning our resins with our Fine Tuners such as FT1 and LB1 Bio. Our Fine Tuners are ideal for overcoming the printing limitations of closed mode "black box" printers.
Typical printing problems and solutions
The picture below on the left is a typical example of bleeding evidenced by support fusing or merging due to overcure beyond limits in the z direction, while the picture below on the right is a clear example of bleeding evidenced by poor resolution due to scattering in the xy directions.
- poor print resolution shown as print and supports overgrowth (bleeding) beyond specifications due to excessive cure beyond specifications/limits:
- a decrease of light power and exposure time will improve resolution if your printer permits it
- an increase of our Fine Tuner LB1 Bio at small dosage will improve resolution significantly in clear and colored resin systems. Additions are recommended in small steps *
- a decrease of dosage of Fine Tuner FT1* with the original resin will improve resolution in clear and colored resin systems
- poor printability shown as the resin does not print nor adhere on the build platform and/or prints have missing parts due to under cure
- an increase of power and/or exposure time (for curing both, the first 2 adhesive layers and the standard layers) and/or dosage of Fine Tuner FT1 will increase adhesion on the build platform and will help to print the supports and the print if they were too soft due to undercure
- poor printability shown as the resin does not print and/or prints have missing parts or suffer separation from supports during printing due to over cure of the resin (common when printing brittle 3D resins)
- a decrease of power and/or exposure time and/or Fine Tuner FT1 will make the supports and print less brittle
- an increase of our light blocker Fine Tuner LB1 Bio will make the supports and print less brittle
- an increase of supports density and tip size will also help to resolve separation of the print from the supports
The use of a flat printed simple but detailed model such as the shown coins is recommended for fast tuning our 3Dresyns to your printer settings
Fine Tuning clear and colored 3D resins
To obtain better quality prints for different layer thickness, we recommend adjust:
- the light power and exposure times if your printer permits it
- the dosage of Fine Tuner FT1 and LB1 Bio in small steps until optimum results are obtained. Note: avoid overdosing FT1 and LB1 Bio.
Opaque colored resin systems do not usually require significant dosage of Fine Tuner LB1 Bio since dyes and especially pigments act as efficient light blockers, improving significantly the XYZ resolution. Light colored and clear resins usually require higher dosage of light blocker to avoid overcure beyond specifications and/or support merging.
3D printing Guidelines: Fine Tuning Process
Step 1: Select your layer thickness, typically between 10-100 microns, for example, 50 microns as standard for your clear or colored resin
Step 2: Select your print settings, supports density, tip size, power and exposure time if your printer permits it.
High power printers tend to cause significant bleeding and require high dosage of light blockers. If your printer permits it, decrease the printer power when massive bleeding occurs in between the supports (support merging and curing as a block as in the shown picture before) to reduce the required Fine Tuner LB1 Bio dosage.
In order to select your optimum power and exposure time this simple and fast Curing Rate Table can be performed:
- Apply the liquid resin on a glass slide and position it on the resin tank in the printer at your chosen or fixed light power and cure it for example for 5 seconds.
- Then, remove gently with tissue paper the unreacted liquid resin from the glass slide (always cleaning its surface gently with isopropanol) and measure with precision the thickness of the cured resin (if any in too short exposure times) with a caliper or micrometer (tare it with precision and enough pressure with the glass thickness, normally of 1 mm).
- Repeat the cure test again with fresh resin but with a longer exposure time, for example, 10 seconds, then remove the unreacted liquid resin with a paper, clean and measure again the thickness of the cured resin.
- Repeat this process with longer exposure times, for example 15, 20, 25, 30, 50 and 70 seconds.
A Curing Rate Table can be easily done representing exposure times, for example 5, 10, 15, 20, 25, 30, 50 and 70 seconds in DLP and LCD printers (these times can be varied if needed to adapt to different print speeds and resin systems), versus thickness of the cured resin at each exposure time. If your printer is an open mode laser based SLA printer adapt the laser exposure settings accordingly. If your printer is a closed mode printer, which does not allow any exposure time changes, then the use of our Fine Tuners FT1 firstly to adjust print speed of our 3Dresyns to your printer, and secondly the use of Fine Tuner LB1 Bio to maximise resolution will overcome this limitation.
If your printer supplier provided the light power across your resin tank, in mWatt per cm2, then, by multiplying power by exposure time, the energy dosage in mJoule per cm2 can be easily calculated for your different exposure times. This is ideal for undertaking scientific and professional 3D printing.
Alternatively a radiometer, measuring light in the wavelength range of your printer, commonly 385 or 410 nm, can also be used for measuring the light power of your DLP and LCD printer across the resin tank.
Considering that a z layer thickness of 50 microns has been chosen for printing, the exposure time needed to cure the resin and have succesful prints, will be the time required to cure at least one layer of 50 microns. This obvious asumption is commonly ignored by beginners.
When too high power and/or long exposure times are chosen (usually exposure times longer than the needed for curing more than 2 layers, for example more than 100 microns) often resolution problems appear, "bleeding", because the accumulated excessive energy dosage provokes the cure of the resin around the print, beyond its limits or specifications.
Example of a Curing Rate Table, where the thickness of cured resin is represented vs different exposure times:
|Exposure time (seconds)||Thickness of cured resin (microns)|
|5||Example: 0 uncured|
|10||Example: 30 soft , poor adhesion|
|15||Example: 60 cured, better adhesion|
|20||Example: 120, well cured, good adhesion|
Example: 130, well cured, good adhesion
Example: 140, well cured, good adhesion
Example: 150, well cured, very good adhesion. Ideal exposure time for printing the first 2 adhesion layers
Example: 170, well cured, very good adhesion
Normally the optimum exposure time is the time needed to cure in between at least one and less than two layers,in this example, the time to cure between 50 and 100 microns, which is approximately around 14 and 18 seconds. In order to increase accuracy is recommended to repeat the cure test table with exposure times closer to our print specifications, for example 10, 12, 14, 16 and 18 seconds.
As general rule, the closer exposure times used for curing just above one layer the higher the final print resolution for a given light power. We normally recommend to initially start printing with the exposure time needed to cure 1.5 layers. Depending on results, in a second print, the chosen exposure time can be reduced by using the time required to cure eg 1.1-1.2 layers with the goal of improving resolution and detail in steps.
In order to have good adhesion of the resin on the build platform, is important to print at least firstly 2 adhesive layers, of any print work, at long exposure times to ensure optimum adhesion and good printability.
As rule of thumb use for curing the adhesive layers 4 times the standard exposure time. Alternatively, more scientifically, use a exposure time where the resin showed optimum adhesion and cured well on the glass slide. In this example, in 50 seconds the resin cured well and had very good adhesion on the glass slide (see example on the Curing Rate Table above), so this time can be chosen for curing the first 2 adhesive layers of the print. Once the exposure times have been chosen, then the next step is:
Step 3: Start printing using 2 adhesive layers (use the exposure times as already explained) and for standard layers use initially the exposure time needed to cure 1.5 layers.
Note: after ordering our resins, upon request (just send us an email to info@3Dresyns.com) several calibration stl files can be sent for fine tuning our resins in your printer).
Step 4: Evaluate the quality of your print.
Option 1: If you are fully satisfied with the quality of your print, then it is not necessary to fine tune our 3Dresyns further.
Option 2: If you are not fully satisfied with the quality or detail of your print it is necessary to fine tune our 3Dresyn and/or your printing settings. Depending on the origin of the print quality problem, different solutions are available.
- If the problem is caused by undercure of the resin an increase of exposure time (eg by using the time needed to cure 1.7-1.8 layers) or an increase of dosage of Fine Tuner FT1 is recommended*. This is reflected by either the print does not adhere to the build platform or the supports and the print are too soft resulting in breaking and separation of the prints from the build platform. Sometimes, the base or the print may break and have missing parts
- If the problem is caused by overcure of the resin a decrease of exposure time (eg by using the time needed to cure 1.1-1.2 layers) or a decrease of dosage of Fine Tuner FT1 is recommended (eg diluting its concentration in small steps*) or an increase of dosage of Fine Tuner LB1 Bio. In this case the supports may be too brittle resulting in breaking and separation of the prints from the build platform at the tip of the supports. If the resin prints well but has no definition or the supports merged or fused the problem is cause by overcure in the xy or z axis beyond limits/specifications due to the combination of excessive power, exposure time, too much Fine Tuner FT1, too little dosage of Fine Tuner LB1 Bio or color. Solutions:
- the light power and exposure time can be decreased (eg by using the exposure time to cure 1.1-1.2 layers)
- the concentration of Fine Tuner LB1 Bio can be increased in small steps or in bigger steps* if there is excessive bleeding or overgrowth beyond limits/specifications. Note: an overdose of light blocker may slow down the cure too much and causing print failure (eg separation from the build platform or breaking of supports or parts of the print). When this happens is better to dilute its content with fresh resin rather than overdosing with an increase of Fine Tuner FT1* since the combined effect may cause print failure because the thickness of the cured resin may end up being smaller than the chosen Z layer thickness due to excessive light filtering, for example, less than 50 microns (in this case, layers will not cure nor adhere). Remember to repeat the Curing Rate Table, with your desired exposure time range, each time there is any change of power and/or dosage of our Fine Tuners.
Following this methodology the optimum dosage of Fine Tuner FT1 and LB1 Bio can be evaluated for your specific printer settings.
"The optimum print quality, speed and mechanical properties will be achieved with the lowest possible dosage of Fine tuner FT1 to ensure printability and with the lowest possible dosage of Fine tuner LB1 Bio to have maximum resolution."
The optimum addition of our Fine Tuners FT1 and LB1 Bio will be found when the print quality is at its highest, further additions of our Fine Tuners will be excessive and printability, resolution and mechanical properties will start to decrease (the prints might become too fragile or not print).
Once the optimum is known (remember to record and report it) since it can be used for your next prints and can be made ready to use for your next orders!
Please take into account that our different 3Dresyns, from ultra hard and tough to elastic, may require different levels of post added Fine Tuners.
We hope you get the best results from your prints!
Enjoy 3D printing with our 3Dresyns!
*Please contact us at: info@3Dresyns.com