Titan is a remarkable printer, and it will deliver accurate, precise and consistent parts if you understand how to use it correctly and adopt the recommended digital file modification.

When using high resolution LCD screens 460nm polymerisation allows consistent and repeatable cure through depth, across the build area and across different Titan printers.

3D printing with resin (stereolithographic printing) by laser, DLP or LCD systems and powder bed fusion 3D printing (SLS and MJF) have the highest tolerances of commercially available plastic 3D printing technologies. Compared to machined accuracies, resin and powder 3D printing tolerances fall between standard machining and fine machining tolerances.

These are the terminologies when discussing accuracy:

Accuracy

Accuracy is how close a measurement is to true value, which is derived from comparing the measured value from a Titan part to the dimensions designed in CAD.

Precision

Precision is the repeatability of a measurement, which means how much you can rely on Titan to produce your expected results, every time.

Tolerance

Tolerance is how precise the critical elements of a part need to be, generally, achieving tighter tolerances means higher manufacturing costs, Titan’s pixel pitch is a factor in determining this.

Tolerancing in 3D Printing

In traditional machining, tighter tolerances are exponentially related to increased cost. Tighter tolerances require additional and slower machining steps than wider tolerances, so machined parts are designed with the widest tolerances allowable for a given application.
Unlike machining, 3D printing has a single automated production step. Tighter 3D printing tolerances may require more effort in the design stage, but can yield significant savings in time and costs in prototyping and production.

Part design and preparation

Designing the model to suit large format LCD Additive Manufacturing is essential in achieving print success. The orientation of the part to position the leading angle correctly, its support network and the design of high aspect ratio thin walls are all critical in avoiding warpage. Our Customer Service department will assist you in learning how to orientate and support your type of geometry and share with recommendation on how to design your models for Titan. All different categories of geometry require different treatment, and we can provide guidelines.

Post processing

Titan comes as part of a full eco-system with a transfer unit, Wash XL and Cure XL units. This enables the parts to maintain isotropy by being washed and post exposed on the platform. The wash solution is designed to remove excess of resin while not reducing mechanical integrity. The combination of heat and double wavelength light fully cures the parts and the constant rotation ensures that curing is delivered evenly to all sides, removing the possibility of warping.

Finishing

Finishing steps for 3D printed parts assemblies commonly include de-supporting, sanding support artefacts and spray painting. Sanding an active surface is a reasonable method for achieving the correct fit if the part is a one-off, because less tolerancing work is required in the design phase, but with larger assemblies, or when producing multiples of something, proper dimensional tolerancing is essential.

Material selection

Resins that print successfully provide a compromise between the desired end use properties and the temporary green strength (modulus before post-curing) necessary to hold the weight of the part and withstand the shrinkage forces that are exerted during printing. Bottom-up printing is more physically demanding on the green state of a part than printing top-down. It is always the case that the immediacy of rapid double bond conversion is an advantage in end-use properties and a disadvantage in part creation. Poorly formulated resins can exhibit very high green strength achieved by high functionality of the monomers and then lead to significant shrinkage and warpage. The effects of this are more evident in large parts. Photocentric select the chemical raw materials carefully to deliver the necessary short terms properties while still delivering the essential long-term functionality.
In addition to resin formulation optimisation, compensation factors in every Photocentric resin print profile are tailored to deliver accurate parts.

We set up a full 1.2m high test print and then measure all the elements of the part, relative to each other.

Build volume accuracy

You will be able to achieve within +/- 0.10% volumetric accuracy in printed parts compared to CAD.

Build volume repeatability

To test repeatability, we set a file up with 112 cubes (10x10x10mm) distributed evenly across the platform and print them at 100µm layer thickness. With repeated processing, measuring and comparing the cubes, we can determine that the x:y tolerance across the build is within +/- 100µm.