xABS3843 Application Notes

Introduction

Nexa3D xABS3843, Matte-Black was developed with material partner Henkel. This is a high-performance photopolymer material that is used to print parts for a wide variety of applications. It exhibits excellent flexural and tensile properties. High opaqueness print highly accurate parts suitable for indoor and outdoor applications. Matte finish eliminates unwanted reflections and glare. 

Printing Tips for End-use parts

xABS3843 is an easy-to-print, slow curing, high accuracy material with a matte black finish. This material has good toughness and impact resistance allowing it to be used with snap fits and other features requiring up to 70% elongation. This makes it a great choice for functional parts. Additionally, xABS3843 is abrasion-resistant and can hide light surface scratches. Parts are easily sanded, painted, and glued during post-processing.

Since xABS3843 is slow curing, printing at high power setting is recommended. Good dimensional accuracy is expected on upskin and sidewalls. Down-skin (facing build platform) angles should be above 30° from horizontal to avoid deformation during peeling.

Adhesion to Build Platform

xABS3843 adheres very well to the build platform, and if printing parts directly on the platform, limited contact area is recommended or parts may fracture during removal. Printing on supports is recommended.

Use a stiff, sharp-edged spatula that could be pushed between the part and the build platform.  

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Bottom surface fractured during removal from platform

xABS3843 support structures are not brittle and can be squeezed and twisted to separate them from the printed part. Large contact sizes can result in divots when torn off; use of cutters for larger contact points and cones is recommended. Use contact dimension below 0.4mm 

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Divots may form when removing supports > 0.4mm (lower part)

Wall Thickness

Wall thickness should be kept above 0.6mm to avoid waviness and knife edges must be avoided with this material. When printing walls below 1mm, reduce the peel and retract speeds to 100 mm/s.

Single layers printed at 100 micron may deform during membrane peel or retraction, resulting in poorer down-skin surfaces and a higher min-wall capability than rigid materials.

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Walls under 0.6mm may wrinkle, and are best printed aligned with Z-axis

 

xABS3843's toughness and matte finish additives result in relatively low stiffness of green parts.  Horizontal layers require very tight support spacing, or rips and bubbles in the first few horizontal layers are expected between the first few layers. Avoid large surfaced below 30° when possible, or reduce influence radius of supports to 1.2mm.

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Large horizontal surface supported with 3mm influence radius.

Walls thicker than 5mm will only case harden in post-cure and may have lower core strength than demonstrated with the validated workflows. Minimize this by curing at temperature or post-baking.

Ageing

xABS3843 exhibits a loss of about 50% of the elongation after aging for a few days at moderate temperatures, with an improvement in strength and stiffness. Extended cure and post-bake will pre-age the material so it will be stable in the application.  

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Scaling Corrections

xABS3843 may shrink differently depending on the level of cure and drying. Here are some typical correction factors for different conditions if you are looking to achieve tight tolerances. Refer to the scaling optimization instruction to determine correct scaling for your parts. 

1.003-1.004x (green part vs stl)

1.005-1.006x (cured 1hr at room temp)

1.006-1.009x (cured 1hr at 60°C)

1.013-1.015 (cured 1hr at room temp and baked 2 hrs at 120°C)

Post Processing

Validated Workflows

WASH

CURE

Post-Bake

Tensile Strength

Elongation

2-4 min wash in xCLEAN & Rinse in IPA

60 min in xCURE @ room temp

N/A

32 MPa

50%

2-4 min wash in xCLEAN & Rinse in IPA

60 min in xCURE @ 60°C

N/A

49 MPa

44%

2-4 min wash in xCLEAN & Rinse in IPA

60 min in xCURE @ room temp

2 hrs @ 120°C

60 MPa

47%

 

Part removal

For very thin features, it is a good idea to clip off the supports connected to these features before removing the remaining support structure.  xABS3843 is moderate-viscosity resin that wets to the part surface. It can easily get trapped in small cavities or in dense support structures. Removing dense supports prior to washing is recommended.

Green parts are very hydroscopic, so avoid contact with water or storing in humid environments prior to post-cure.

Washing

Blind holes or long narrow holes require manual cleaning with a syringe of solvent or pressurized air. Washing with solvent heated to 40°C and with ultrasonic agitation might facilitate cleaning without manual intervention on tight spots. 

Wash immediately after printing and limit exposure to humidity or water. xABS3843 is hydroscopic when in the green state. Rinse off xCLEAN with IPA or rinse only in IPA to allow quick drying times and prevent prolonged exposure to solvent. Many customers washing in xCLEAN in two steps (one clean one dirty). 

Excessive exposure to solvents or rinsing in dirty solvent may cause the matting agent (a white powder-like material) to raise to the surface. If this occurs, it can be removed with a soft brush after curing.

Curing

Post-cure xABS3843 for 60 min in the xCURE unit. Ensure parts are fully dry before post cure. Heating the curing chamber prior to curing will help evaporate off residual solvent and moisture.

Thin, flat panels may deform during curing. If both sides of a panel aren't irradiated evenly, then leave some supports or other structures to constrain the shape until fully cured. 

 

Updated

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