Siraya Tech Rebound 55A Black User Manual

1. Introduction

Rebound 55A Black is the first resin in Siraya Tech’s new elastomer series, designed for high flexibility, fast rebound, and reliable elasticity. With a 55A Shore hardness, it’s ideal for prototyping soft, shock-absorbing parts and flexible consumer products.

Compared to traditional elastic resins, Rebound 55A recovers shape faster after compression while maintaining structural integrity. Early tests show strong durability under repeated compression, making it well-suited for demanding prototypes.

Position in Our Lineup:
Rebound 55A is softer and rebounds faster than Tenacious Flex (55A vs. 70A), making it ideal for applications that need quicker shape recovery. While Tenacious offers better tear resistance, Rebound focuses on compression performance and bounce-back speed.

2. Key Features

  • Fast Rebound Action
  • Promising Durability
  • 55A Shore Hardness – Balanced Flexibility & Strength
  • Versatile Prototyping

3. Printing Preparation

Rebound 55A Black has a very high viscosity. Careful preparation is essential for success

  • Resin Handling (Important!)

DO NOT SHAKE: This resin contains no pigments that settle. Shaking is unnecessary and will only introduce air bubbles, which can negatively impact print quality. Handle the bottle gently.

  • Printer Settings 
    • Printer Compatibility: Compatible with most LCD and DLP printers (405nm) with a panel size less than 12 inches (e.g., Elegoo Mars/Saturn series, Anycubic Photon series, Phrozen Sonic series).
    • Large Printers (>12 inches): Due to the very high viscosity, printers larger than 12 inches may face challenges. Please consult Siraya Tech support before attempting prints on larger format machines.

    • · High Viscosity Settings: Pay close attention to Lift Speed and Wait-After-Retraction (Light-Off Delay) settings in your slicer. Slower lift speeds and longer delays are crucial to allow the thick resin time to flow back under the build plate between layers.  

      Follow the detailed recommendations in the Siraya Tech Guide for High Viscosity Resins.

4. Build Platform and Vat Preparation

  • Ensure the build platform is perfectly level and meticulously clean.
  • Lightly sanding the build platform surface with fine-grit sandpaper can significantly improve first-layer adhesion.
  • Clean the resin vat thoroughly, ensuring no cured resin debris is present.

5. Temperature Control

  • Optimal Range: Print in an environment between 25°C and 35°C (77°F - 95°F) for best results.
  • Minimum Temperature: The absolute minimum printing temperature is 20°C (68°F). Printing below this may lead to failures.
  • Cold Environments: If your printing area is cool, use a suitable heating solution (like a heater or enclosure) to maintain the optimal temperature.
  • Pre-warming Resin: User can heat up resin by using a hair dryer to warm up the resin in the vat before printing. We recommend a thin later of resin for starting the print.

ST0050 rebound resin 55A - heat

6. Recommended Printing Process (CRITICAL STEPS)

Due to the extremely high viscosity, follow these steps carefully:

(1) Initial Pour: Pour only a small amount of resin into the vat – just enough to cover the estimated area of the first few layers. Pour slowly to minimize bubbles.


(2) Spread Resin: Use a silicone spatula to gently spread the small amount of resin evenly across the FEP film in the expected printing area.

ST0050 rebound resin - print process for bottom layers

(3) Settle Time: Allow the resin to settle for 5-10 minutes before starting the print to let any bubbles rise and dissipate.

(4) Start Print & Monitor: Begin the print. Watch the build plate's initial descent.

(5) Handle Sensor Warnings: On printers with leveling sensors, the plate might stop before full descent due to resin resistance, triggering a warning (e.g., "Platform uneven" or "Not Enough Resin"). If this occurs, bypass the warning and proceed with the print. The printer should still function correctly.

Handle Sensor Warnings - ST0050

(6) Add More Resin Gradually: Once the first layer begins printing successfully and the build plate is down, slowly add more resin into the vat, pouring near a corner away from the print area. Add only enough resin needed for the print height.

Add More Resin Gradually

(7) Monitor Initial Layers: Closely watch the first 5-10 layers to confirm successful adhesion to the build platform.

7. Cleaning (Thoroughness Required)

Rebound 55A cleans with standard methods, but thoroughness is key.

  • Drain: After printing, let the part hang and drain thoroughly over the vat for at least 10 minutes.
  • Two-Stage Wash (Recommended): Use 95% or higher concentrated Ethanol or IPA.
    • Bath 1: Wash the part for 10 minutes in a container of used/dirtier solvent (a standard wash station without ultrasonic is suitable). This removes the bulk of the resin.
    • Bath 2: Transfer the part to an ultrasonic cleaner containing fresh, clean solvent and wash for another 10 minutes.
  • Temperature: Ensure the cleaning solvent is not too cold, as this reduces effectiveness. Never heat flammable solvents like IPA or Ethanol.
  • Dry Immediately: Immediately after removing the part from the final cleaning bath, use compressed air or a hairdryer on a cool setting to blow off all residual solvent. This prepares the part for the essential heat treatment step.

8. Heat Treatment (UNIQUE & ESSENTIAL STEP)

This step is crucial for evaporating absorbed solvent and achieving final properties. Do this BEFORE Post-Curing.

(1) Heat: Place the cleaned and surface-dried part in a drying device (like a food dehydrator or a convection oven with good temperature control) set to 50°C (122°F).

(2) Duration: Heat the part for a minimum of 60 minutes. 90 minutes is recommended for optimal solvent evaporation.

(3) Visual Cue: As the solvent evaporates during heating, you should observe the part's color transition from a slightly translucent black to a deeper, more opaque black.

(4) Check Surface: After cooling, check the surface. If it still feels sticky, repeat the Cleaning (Step 6) and Heat Treatment (Step 7) processes.

9. Post-Curing

Ensure the part is completely clean, dry, and has undergone the Heat Treatment step before post-curing.

(1) UV Source: Use a UV curing station with a 395-405nm wavelength light source.

(2) Time: Cure for approximately 15-20 minutes.

(3) Rotation: Rotate the part periodically (e.g., every 5 minutes) to ensure even exposure on all surfaces. (Optimal curing times may vary; check Siraya Tech resources if specific recommendations become available).

10. Potential Applications

  • Protective Gear Prototypes: Sports pads, cushioning elements
  • Shock-Absorbing Components: Prototyping dampeners, buffer elements
  • Consumer Products: Flexible phone cases, grip elements, comfort pads
  • Industrial Prototyping: Seals, gaskets, vibration dampeners, grip surfaces
  • Sports Equipment Prototypes: Handle grips, impact cushioning elements

11. Safety Precautions

  • PPE: Always wear nitrile gloves, safety glasses, and a suitable respirator when handling uncured resin.
  • Ventilation: Work in a well-ventilated area.
  • Skin Contact: Avoid skin contact. If contact occurs, wash immediately and thoroughly with soap and water.
  • Disposal: Dispose of uncured resin, contaminated solvent, and disposable materials according to local environmental regulations.

12. Storage

  • Store Rebound 55A Black resin in its original opaque bottle in a cool, dark place away from direct sunlight.
  • Keep the bottle tightly sealed when not in use.
  • Use within the recommended shelf life for best results.