Fast and accurate Instructions for Use "IFU" for DLP & LCD printers

These fast and accurate Instructions for Use "IFU" can be used for printing our 3D resins with SLA, DLP & LCD printers: 

Standard settings for printing most of of our 3D resins in most SLA, DLP & LCD printers:

• Z layer or slice height or thickness is typically between 50-100 microns (0.05-0.1 mm). Lower or higher are also printable for most 3D resins
• Cure or Exposure or z layer or slice or thickness times are typically between 1-10 seconds for the fastest resins and 10-20 seconds for the slowest resins 
• Depending on the power of your printer, the optimum exposure times will increase or decrease. Follow our detailed Instructions for Use. Measure and fill up the data, cure thickness vs exposure time, in the curing rate table for your specific printer specifications. Alternatively, order online the curing the table for your ordered 3D resins measured with similar light power specifications with this light meter*
• Typically 3 initial, also known as adhesion, or bottom, or base, layer, or slice, or cure bottom count exposures of 80-100 seconds are enough for having very good adhesion on the build platform for most 3D resins
• Z lift & retract speed: low, medium, or high value of the scale (non critical for most 3D resins)
• Light off delay/off time/wait before & after print: 0.1-0.5 seconds (non critical or most 3D resins)
• Z Lift after print distance: 5-10 mm (non criticalfor most 3D resins)
• Printing temperature: before printing warm viscous 3D resins, protecting them from room light to prevent their light curing, to around 30-35ºC to reduce their viscosity and adhesion to the resin tank
• low viscosity resins do not require any warming

Background

• Different printers have different light power across the vat for printing
• Printers have different light power across the vat, exhibiting higher power in the centre than on the sides and borders
• Light power of printers decay upon time
• 3D resins need light for curing them in the printer
• Slow 3D resins need longer exposure times than faster 3D resins
• Low light power printers need longer exposure times than high light power printers for curing and printing 3D resins
• The higher the chosen z layer thickness the longer the exposure time required for curing and printing
• The exposure times for adhering the resin to the build platform and for curing and printing each layer depend on the 3D resin, the light power of the printer, and the chosen z layer thickness 

For more info read: 

Consequences

• Light exposure times need to be correctly input in the printing settings to succesfully print the 3D resins in the printers 
• Each 3D resin needs specific specific exposure times for adhering the resin to the build platform and for curing and printing each layer
• Depending on the 3D resin, the light power of the printer, and the chosen z layer thickness the exposure times and printing settings need to be input 

Solution

The 3Dresyns team has designed this fast and accurate instructions for Use IFU for finding in just simple steps the best printing settings of our 3D resins in your specific printer.
Our recommended fast and accurate calibration process is ideal for getting in just few easy steps the optimum exposure times in your printer.

Order the recommended curing rate table for each ordered 3D resin cured at 405 nm with a similar light power to your printer for 40 Euro. For getting exact exposure time values we recommend you ordering the same light meter as ours, the Chitu Systems Digital UV Light Meter. 

The ordered curing rate table (Curing Rate Table) can be much more accurately measured after sharing your exact printer power since this will permit the 3Dresyns team to measure the curing rate table of your ordered 3D resins with the same power as yours since we will match your exact light power (light power matching) for fast & easy finding your optimum printing settings.

Alternatively, you can measure your own curing rate table as clearly explained in our Detailed Instructions for Use IFU for DLP & LCD printers to save you 40 Euro for each ordered 3D resin. The same curing rate table can always be used for future orders of the same 3D resin specifications. 

Fast and accurate calibration system: calibration protocol

• Measure the light power of your printer in the center of the vat with the recommended light meter
• Send us the measured light power in mW/cm2
• The 3Dresyns team will send you the ordered curing rate table with the same light power to your print for 40 Euro, which can be optionally ordered with each 3D resin before check out
• Select your z layer thickness, or the thickness of each printed layer, typically between 10-100 microns, for example, 50 microns as standard for high resolution printing
• Select your printing settings, supports positioning, density, tip size and exposure time

How to choose the optimum exposure times?

It is crucial to choose the right exposure times from the ordered Curing Rate Table which is a fingerprint of the kinetics of your chosen 3D resin in your printer.

How can you choose the exposure times from your own or from the ordered Curing Rate Table "CRT"? By choosing the exposure time needed for curing a layer thickness similar (or a bit thicker) to the chosen z layer thickness.

Example of the Curing Rate Table "CRT" of a reference 3Dresyn x with lot y at certain light power of z mW/cm2 at 405 nm:

 The ordered curing rate table measured with similar or with the same light power of your printer, in case you measure it with the same recommended light meter, represents the cured layer thickness in microns or mm (1 mm=1000 microns) of the chosen 3D resin at 2, 5, 10, 15, 20, 25, 50, 75, and 100 seconds.

The reported values of thickness of each cured drop of 3D resin include an evaluation or comment about its perceived strength in the curing rate table.

All 3D resins pass from liquid to solid state, through a green state, in which the resins can be too tender or soft to resist the peeling, or separation, or lift from the vat or resin tank during printing.

From the curing rate table 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 between one and two layers, in this example, the time to cure between 50 and 100 microns.

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 at least 2 adhesion layers at long exposure times at around 75 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 in case you are interested in printing small parts and want to have a feeling of the achievable xy resolution. Use 2 adhesion layers (use the exposure times as already explained) and for standard layers use initially the exposure time needed for curing 1.5 layers:

• 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 100 microns or with 40 z layers of 50 microns. This fast calibration file consumes very little resin and provides a fast pro´ç`of 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 fast and accurate calibration

• cost effective light meter of 50 Euro (optional) for light power matching (synchronisation) and for providing the ordered curing rate table with maximum accuracy, measured with the same light power as the light power of your printer

For more detailed IFU read:

• General Instructions for Use "IFU" for SLA, DLP & LCD printers
• Detailed Instructions for Use "IFU" for DLP & LCD printers

For more specific IFU read:

• Fine Tuning additives for custom fine tuning of printing speed, resolution, precision, and dimensional accuracy
• IFU for mixing additives with 3D resins
• IFU for conductive resin systems

For cleaning and post processing IFU read:

• IFU for ultra gloss and transparency of clear prints
• IFU for colored 3D prints
• IFU for biocompatible resins
• IFU for water soluble sacrificial 3D printed resins
• IFU for solvent soluble sacrificial 3D printed resins

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