Instructions for Use (IFU) for SLS Cold Fusion of Metal, Ceramic and Exotic Powders
Step-by-step instructions for SLS and cold fusion powder workflows using 3Dresyns® Cold Fusion powder binders, fusible co-binders, optional pore formers and functional metal, ceramic, polymer and exotic powders.
This IFU describes how to run SLS and cold fusion powder workflows in practice, from powder mixing to printing, debinding and sintering, using the 3Dresyns® Cold Fusion binder range.
In cold fusion the functional powder (metal, ceramic, polymer or exotic) is not melted by the laser. The laser melts a fusible phase — a co-binder (PLA for water routes, Nylon for the CF1 solvent route) or, in the case of the self-sufficient CF3 binder, the binder itself — that bonds the particles into a green part. The water- or solvent-soluble binder is then removed by its debinding route to open a pore network, and the remaining organics are removed by thermal debinding before the functional powder is sintered. An optional crosslinked PMMA pore former can be added for controlled porosity. Use this page to set up and validate your specific powder system.
For background, read: About Cold Metal Fusion (CMF), Cold Ceramic Fusion (CCF), Cold Polymer Fusion (CPF) and Cold Exotic Materials Fusion.
Cold fusion separates shape generation from final material performance. The laser only fuses the binder + co-binder to form the green part; the functional powder is never melted. Final density and strength come from the downstream debinding and sintering steps, which must be engineered together with the printing stage.
Three to four functions are distributed across the blend: a powder binder (3D-POWDER CF) that wets the functional powder and is later removed by its debinding route (water or eco solvent); a fusible co-binder (PLA for water routes, Nylon for solvent routes) that melts and coalesces under the laser to give the green part its structural cohesion and toughness; the functional powder that forms the final sintered part; and an optional sacrificial pore former (crosslinked PMMA) added only when controlled porosity is required.
Note the division of roles: the fusible co-binder, not the binder, provides green-part cohesion. The optional PMMA pore former is crosslinked and does not melt — it holds its spherical shape and burns out cleanly to leave controlled pores; it is not a fusible phase.
CF3 exception: CF3 SD Bio is a self-sufficient binder — its ultra-low melting point lets the laser fuse it directly to give green-part cohesion, so it does not require a Nylon or PLA co-binder. A co-binder is optional, only for demanding powder systems (e.g. heavy metal powders or large parts).
The Cold Fusion binder range
Binder selection matrix
Select the binder by debinding route, thermal behaviour and target powder family. All CF binders are bio based and paraben free. The cold eco debinding liquid DS1 Bio is the matching debinder for the solvent-debindable binders (CF1, CF3, CF5).
| Parameter | CF3 SD Bio | CF1 SD Bio | CF2 WD Bio | CF4 WD Bio | CF5 SD Bio |
|---|---|---|---|---|---|
| Debinding route | Eco solvent (DS1 Bio) | Eco solvent (DS1 Bio) | Water (60–100 °C) | Water (60–100 °C) | Eco solvent (DS1 Bio) / assisted |
| Melting temperature (ISO 11357) | 55–65 °C (lowest-melting solvent route) | Low melt viscosity grade | 160–166 °C | 55–60 °C | Low thermal degradation (<270 °C) |
| Average particle size | < 150 µm | Fine powder | < 100 µm | < 250 µm | Fine powder |
| Hygroscopicity | Keep cool & dry (softens when warm) | Keep dry | Very low / non hygroscopic | Low–moderate (keep dry) | Keep dry |
| Recommended fusible co-binder | None required (self-sufficient; optional for demanding systems) | Nylon 12 / 11 (or PP, PE) | PLA20-80 | PLA20-80 | Used with CF2 (no Nylon — see note) |
| Optional pore former | PMMA 20-50 (crosslinked, sacrificial) | PMMA 20-50 (crosslinked, sacrificial) | PMMA 20-50 (crosslinked, sacrificial) | PMMA 20-50 (crosslinked, sacrificial) | PMMA 20-50 (crosslinked, sacrificial) |
| Core positioning | Lowest-melting solvent-debindable binder; self-sufficient cold-printing on minimally heated beds | Universal solvent-debindable; broad powder wetting | Universal water-debindable; robust, easy-to-handle green parts; high resolution | Water-debindable; low-temperature fusion, gentle activation | Low-thermal-degradation binder for high-performance polymers |
| Typical workflow | Cold Metal, Ceramic, Polymer & Exotic Powder Fusion (cold bed / low energy) | Cold Metal, Ceramic, Polymer & Exotic Powder Fusion | Cold Metal, Ceramic & Exotic Powder Fusion | Cold Metal, Ceramic & Exotic Powder Fusion | Cold Polymer Fusion (CPF): PEEK, PEKK |
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Choosing the co-binder and the optional pore former
The fusible co-binder depends on the debinding route
The fusible co-binder is the polymer the laser melts and coalesces to build the green part and give it cohesion and toughness. The correct choice is governed by the binder's debinding route. A separate, optional pore former (crosslinked PMMA) is added only when controlled porosity is wanted — it is not a fusible phase.
| Parameter | Water-debindable route (CF2, CF4) | Solvent-debindable route (CF1, CF5) |
|---|---|---|
| Recommended fusible co-binder | PLA20-80 (bio-based, clean ash-free burnout) | Nylon 12 / Nylon 11 (or PP, PE) |
| Why | Binder dissolves in water, so the co-binder must not be water soluble; PLA keeps the part shape while water extracts the binder, is bio-based and burns out clean below ~360 °C, and adds toughness that offsets the brittleness of the crystalline binder | No aqueous extraction step, so the co-binder need not resist water; Nylon is the native SLS powder with a validated process window and tough green parts |
| Co-binder behaviour | Semi-crystalline thermoplastic, melts and coalesces under the laser, tough green parts, clean ash-free burnout | Semi-crystalline, tough and machinable green parts (CF1 solvent route). Note: not used for the CF5 PEEK/PEKK route, where Nylon degrades above the sintering window |
| Optional pore former | PMMA 20-50 (crosslinked) when porosity is required | PMMA 20-50 (crosslinked) when porosity is required |
| Bed temperature class | PLA-class (see notes for CF4) | Nylon-class (per printer manufacturer) |
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CF5 exception (Cold Polymer Fusion of PEEK / PEKK): although CF5 is a solvent-route binder, it does not use a Nylon co-binder, because Nylon degrades above the PEEK / PEKK sintering window. CF5 is paired with the water-soluble CF2 binder; CF5 is non-water-soluble and holds the green-part shape while CF2 is washed out in water.
CF3 exception (self-sufficient binder): CF3 SD Bio does not require a co-binder at all. Its ultra-low melting point lets the laser fuse it directly to give green-part cohesion, so it works on its own. A fusible co-binder is optional, added only when extra green strength is needed for demanding powder systems.
- Water-debindable route (CF2, CF4) → fusible co-binder = PLA20-80
- Solvent-debindable route (CF1) → fusible co-binder = Nylon (PA12 / PA11)
- Solvent-debindable cold-printing route (CF3) → no co-binder required; CF3 is self-sufficient and the laser fuses it directly. A co-binder is optional only for demanding powder systems
- Cold Polymer Fusion route (CF5, for PEEK / PEKK) → no Nylon co-binder; CF5 is paired with the water-soluble CF2 binder and the blend is debinded in water. Nylon is excluded here because it degrades above the PEEK / PEKK sintering window
- Optional, any route → add 0-10 wt% PMMA 20-50 (crosslinked) as a sacrificial pore former for controlled spherical porosity and faster debinding of thicker parts; omit for maximum density
- The co-binder gives green-part cohesion; the binder is removed in debinding; the PMMA pore former does not melt and is burned out — three distinct roles
The role of the optional PMMA pore former
3D-POWDER SLS PMMA 20-50 is a crosslinked (thermoset) spherical PMMA. Unlike the fusible co-binder, it does not melt or coalesce under the laser: it keeps its spherical shape through printing and is then removed cleanly during thermal debinding, leaving smooth, near-spherical pores of controlled size.
- Add it when the application needs controlled, interconnected porosity (filters, scaffolds, porous functional parts) or open channels for faster, cleaner debinding of thicker green parts.
- Omit it when maximum sintered density is the goal — the binder removal already opens a pore network for debinding.
- Do not raise laser energy trying to fuse the PMMA: cohesion is provided by the PLA or Nylon co-binder (or by the self-sufficient CF3 binder), not by the pore former.
Powder mixing
Recommended starting composition
Mix in a powder mixer (or similar) at room temperature to ensure full wetting and homogeneous blending. The values below are approximate starting ranges, not specifications: the optimum depends on the functional powder, part geometry and printer, and must be validated for each case.
| Component | Starting range | Notes |
|---|---|---|
| Binder — 3D-POWDER CF (SD or WD Bio) | ~10-20 wt% | Select by debinding route (water: CF2/CF4; solvent: CF1/CF3/CF5) |
| Fusible co-binder (when required) | ~5-15 wt% | PLA20-80 for water-debindable binders (CF2/CF4); Nylon 12 / 11 for the solvent binder (CF1). For the CF5 PEEK/PEKK route, CF5 is combined with CF2 instead of a Nylon co-binder. CF3 needs no co-binder (self-sufficient); add one only for demanding powder systems |
| Functional powder | balance (~65-85 wt%) | Your chosen ceramic, metal, polymer or exotic powder or fiber |
| Optional pore former — PMMA 20-50 | 0-10 wt% | Crosslinked sacrificial pore former; add for controlled porosity or faster debinding of thick parts, reducing functional powder accordingly; omit for maximum density |
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- For best homogeneity and to avoid gravitational segregation between dense functional powder and lighter organic powders, keep particle size distributions as similar as practical and mix thoroughly.
- Keep the finished blend dry and sealed before printing.
- For high-performance polymers (PEEK, PEKK) use CF5 SD Bio combined with the water-soluble CF2 binder. A Nylon co-binder is not used here, because Nylon degrades above the PEEK/PEKK sintering window; CF5 is non-water-soluble and retains the green-part shape while CF2 is washed out in water.
- 3Dresyns can supply custom powder blends to your specifications.
SLS printing process
1. Calibration (recommended)
Calibrate your powder mix before production printing.
- Print 3Dtest1 (3Dresyns flat coin) for rapid optimization of resolution and printing parameters.
- Slice 3Dtest1 using the settings of the closest equivalent polymer powder: PLA-class for CF2/CF4 water routes, Nylon-class for CF1/CF5 solvent routes. For CF3, start from a low-melting / low-energy profile with a cold bed, as it has no co-binder and melts at very low temperature.
- Send the sliced file to the printer and print.
2. Printer setup and printing parameters
The bed temperature follows the fusible co-binder (PLA for water routes, Nylon for the CF1 solvent route), as it is the phase the laser melts to build the green part. For CF3, which has no co-binder, the bed follows the CF3 binder itself and is kept cold (below its melting point). Use the relevant standard SLS window as a starting range and validate recoatability for your blend. Values below are orientative starting ranges, not specifications.
| Parameter | Solvent-debindable cold print (CF3) | Water-debindable (CF4 → low-melting binder) | Water-debindable (CF2 → crystalline binder) | Solvent-debindable (CF1 / CF5) |
|---|---|---|---|---|
| Fusible co-binder | None (CF3 is self-sufficient) | PLA20-80 | PLA20-80 | Nylon 12 / 11 |
| Equivalent powder profile | Low-melting binder itself (no co-binder) | PLA-class | PLA-class | Nylon-class |
| Starting bed temperature (range) | Cold bed, below the binder melting point — orientative room temperature up to ~45 °C; validate recoatability at low bed temperature | ~70–105 °C; the low-melting binder melts at 55–60 °C and acts as a melt plasticizer/wetting agent during printing. Start low and increase as recoatability allows | ~90–105 °C; the crystalline binder melts well above this and stays solid and dimensionally stable | Per Nylon-class printer recommendation |
| If over-melting | Reduce energy dosage (laser power and/or scan speed) and/or keep the bed cooler | Reduce energy dosage (laser power and/or scan speed) and/or lower the bed temperature within the range | Reduce energy dosage (laser power and/or scan speed) and/or slightly decrease bed temperature | Reduce energy dosage (laser power and/or scan speed) and/or slightly decrease bed temperature |
| If poor recoating / caking | Keep the powder cool and dry; verify the blend is dry (the binder softens if the bed or storage is too warm) | Lower the bed temperature and the binder fraction, and verify the blend is dry (most relevant with the low-melting CF4 binder) | Slightly reduce bed temperature and verify the blend is dry | Follow Nylon-class recoating guidance; verify the blend is dry |
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3. Post-processing (green parts)
- Remove parts from the build chamber.
- Clean green parts: remove excess unfused powder manually, typically using pressurized air or a water jet (as appropriate for your material system).
- If surface smoothing is needed, use Cleaning Fluid WS1.
- Recycle unfused powder by filtration/sieving and reuse by blending with fresh powder for the next jobs.
Debinding & sintering
Cold debinding by route
Once green parts are fully cleaned, a debinding step removes part (or all) of the binder system. After debinding, parts are referred to as “brown” parts, then thermally processed to remove remaining binder and sinter the functional particles at high temperature.
| Parameter | Water-debindable (CF2, CF4) | Solvent-debindable (CF1, CF3, CF5) |
|---|---|---|
| Medium | Water (faster in boiling water) | Debinding Solution DS1 Bio |
| Temperature | 60–100 °C | Per binder recommendation |
| Time | x hours, depending on part size and geometry | x hours, depending on part size and geometry |
| Result | Binder removed, opening the pore network for clean thermal debinding | Binder removed, opening the pore network for clean thermal debinding |
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Thermal debinding & sintering (example furnace profile)
- Insert the flask/parts into a preheated oven at 65 °C.
- Ramp 1–2 °C/min up to 250 °C.
- Hold at 250 °C for 60 minutes.
- Ramp 1–2 °C/min up to 450 °C (this stage covers the clean burnout of the organics: the fusible co-binder, e.g. PLA, and the optional PMMA pore former; ensure adequate airflow / extraction).
- Hold at 450 °C for 30 minutes.
- Ramp 2–5 °C/min up to the material-specific sintering temperature.
- Hold at sintering temperature for 180 minutes.
- Ramp down at approximately -2 °C/min, then furnace-cool to room temperature.
Important: Exact debinding and sintering profiles depend on material chemistry, particle size distribution, binder, co-binder and pore-former selection, geometry and furnace atmosphere. Always validate your workflow for your specific powder system and target performance.
Handling & safety
Powder handling, safety and environment
- Dust generation and inhalation: use appropriate personal protective equipment, ventilation and dust extraction.
- Dust explosion risk: fine organic powders dispersed in air can form explosive mixtures and may be ignited by low-energy sources such as static electricity; the risk increases as particle size decreases. Design powder handling to prevent explosive dust clouds and control static, in line with applicable standards (e.g. NFPA 68/69 or local equivalents).
- Reactive powders: certain functional powders (notably fine reactive metals) may be flammable or reactive.
- Solvent routes (CF1, CF5 with DS1 Bio): observe the safety, ventilation and disposal guidance for the debinding liquid.
- Moisture control: keep all powders and blends dry and sealed. CF4 is low-to-moderately hygroscopic and benefits from sealed, moisture-proof storage; CF2 is essentially non hygroscopic with more stable storage and recoating, but the blend should still be kept dry to preserve flowability.
- Comply with all local safety and environmental regulations.
Process validation
Cold fusion parts are highly process-dependent and must be validated across the full manufacturing chain, not only at the printing stage. The printed green part, the binder/co-binder system and every downstream operation must be treated as one coupled process.
- green-part accuracy, cohesion and surface quality
- binder/co-binder compatibility with the chosen functional powder and debinding route
- cold debinding kinetics (water or solvent) and pore-network formation
- thermal debinding behaviour and clean co-binder and pore-former burnout
- sintering shrinkage and dimensional compensation
- mechanical integrity and density of the final sintered part
- recoatability, moisture control and cycle-to-cycle stability
3Dresyns does not assume responsibility for performance obtained under user-defined powder fusion workflows. Final material performance depends on powder characteristics, energy input, binder, co-binder and pore-former systems and post-processing conditions, and must be validated by the user.
Need help selecting binders or defining a cold fusion workflow?
Contact our technical team to align binder selection, co-binder, pore former, powder composition, printer configuration, debinding medium and sintering schedule for your application.
Document reference: IFU-3DRESYNS-CF-SLS-COLDFUSION-EN | Version: 5.2 | Last updated: May 2026