SLA Print Cure Inhibition: Wash, UV, Seal | RUUIPON

An SLA or DLP print inhibits platinum when uncured oligomer, IPA film, or a shadowed undercut never saw enough UV. The tell is local: the cavity face against the print stays tacky; sprues and the jacket back snap. This page is the protocol we actually run before A/B sees that print — wash until the solvent comes off clean, full post-cure including shadows, a barrier coat, then a 20 g witness slug on a hidden land. It is not a general “3D printed masters” overview, and it is not the sticky-face diagnosis article. Skip a step and we will not pour a food well “to see.”

RUUIPON, Bao'an since 2018. Simple 3D is USD $50 when we should stop fighting your print and remodel a pour-ready master. Prototype 3–7 business days after CAD lock — lock includes “this print is chemically quiet.” MOQ 20 pieces per design. Steel/LSR *parts* from a printed *pattern for steel* are a different plant: wydsilicone.com.

Does not apply when the master is FDM you already filled and sealed (texture talk, not oligomer talk), when the print is only a mold box, or when the resin bottle has no name and no post-cure notes. We would not platinum-food a mystery print.

Protocol, in shop order, with the failure that skips each step

1. Scale and material note. A print scaled to 98% plus platinum 0.1–0.3% is a silent stack. Write units and one measured length. Unknown resin is a stop. Confirm: calipers on a printed datum vs the STEP. Fix: reprint or $50 CAD to a master we control.

2. Wash until the solvent is actually clean. Cloudy IPA pouring out of a counter is still resin. Puddles in letters become inhibition islands. Symptom if skipped: tack only in counters and vents; open faces cure. Confirm: last wash looks like unused solvent; no puddle in an “A.” Fix: re-wash, including a soft brush in counters. Do not jump to UV to “lock in” dirty wash.

3. Full UV, including shadows. Windowsill sun is not a post-cure. Undercuts and the build face against the raft are the usual wet zones. Rotate or use a chamber the resin notes describe. Symptom if skipped: build-face tack, jacket fine. Confirm: a slug on the build face vs a slug on a sanded, re-UV’d land. Fix: more UV after a clean wash, then seal. We would not bake platinum onto a still-smelling print.

4. Seal. Barrier coat after UV, not instead of UV. Seal on wet oligomer traps poison under a varnish you then copy. Symptom if skipped: even a well-washed print of some chemistries still strings platinum. Confirm: slug on sealed land vs raw land from the same print. Fix: named sealer, full dry in undercuts. Hairspray is not a sealer.

5. Witness slug, then the production skin. A 20 g puck on a hidden land is cheaper than a 400 g glove. If the puck strings, stop. If it snaps, the box can be poured. Symptom if skipped: you find out on the logo. Fix: always slug food jobs. Craft jobs still slug if the resin is new to us.

Latex gloves on a washed print re-poison the story. Nitrile. Tin leftover on a print you used as a craft mold first: new platinum on that print is a poison recast — seal will not eat tin salts.

Typical shop values

Caption: Typical shop values.

The photo that would prove a quiet print: last wash in a clear cup next to unused solvent, UV log or a note of chamber time, sealed master, snap-cured slug on a coin.

Worked example (anonymized)

Grey DLP mascot, 80 mm, still smelling of wash, buyer wanted a chocolate cavity that week. We declined the hope pour. They UV’d on a windowsill; slug on the build face still strung. We took $50 CAD, rebuilt the mascot with draft on the arms (split, not a one-piece glove), our sealed master, slug snap, production skin in the 3–7 business day window after lock. First couverture witness released. MOQ 20. The smelly DLP stayed a shelf model.

One procurement mix-up

“The STL is the master” is how inhibition lands on a food PO. An STL is a mesh. A pour-ready master is washed, UV’d, sealed, and slugged. Paying tooling is not unrestricted ownership of a print that failed the slug.

We would not recommend

We would not recommend pouring platinum food cavities against a still-smelling SLA.

We would not recommend sealing before the wash runs clean.

We would not recommend skipping the 20 g slug to save an afternoon.

We would not recommend switching the food job to tin-cure to survive a dirty print.

flowchart TD
  A[SLA/DLP offered as platinum master] --> B{Resin named + scale datum?}
  B -->|No| C[$50 CAD or refuse mystery print]
  B -->|Yes| D[Wash until solvent runs clean]
  D --> E[Full UV including shadows]
  E --> F[Barrier coat; dry undercuts]
  F --> G[20 g witness slug on hidden land]
  G --> H{Slug strings?}
  H -->|Yes| I[Do not pour the glove — reprint, more UV, or remodel]
  H -->|No snap| J[Box, A/B, vacuum, jacket]
  J --> K[Food skin only if slug was clean]

What to ask when you're buying

• Will the shop slug a hidden land before the production skin?
• Who owns the print if the slug fails — reprint, or $50 remodel?
• Food vs craft: a failed food slug is scrap, not a wash step.
• Latex in the print room? We want nitrile on platinum jobs.
• Archive the sealed master, not the raw STL only.

RFQ copy-pack

[email protected] · +86 135 3006 2969 · Xinhe Blvd, Shajing, Baoan.

RUUIPON SLA-master protocol RFQ Resin name / printer / layer height Wash: solvent + until-clean? yes/no UV: chamber / windowsill / unknown; shadows rotated? Sealer: name or none Photo: print + intended hidden-land slug Food-contact? yes / craft Qty: slug then sample / MOQ 20 CAD: use this print / need $50 3D

Matched next step: send resin name, wash/UV notes, and whether we may slug before the glove. We will not skip to a food pour. Prototype 3–7 business days after CAD lock. MOQ 20 per design.

Related: 3D-printed masters for RTV, sticky uncured inhibition, mold design service, contact.

FAQ

Is every SLA print going to inhibit platinum? No. Quiet prints after wash, UV, and seal pour every week. Still-wet DLP and mystery bottles are the failures. The slug is the test, not a forum list of “safe” resins we will not invent here.

Can I UV longer instead of washing? You will lock dirty wash under a crust. Wash until clean, then UV.

Does a coat of PVA replace UV? No. Seal after UV. Seal on wet oligomer hides the smell and still poisons the face.

If the slug fails, do I still wait 3–7 days? The prototype clock starts after CAD lock, and lock includes a quiet master. A failed slug is not lock.

When is the $50 CAD the right call? When the print will not quiet down, when scale is wrong, or when we need draft/split the STL does not have. Fighting a poisonous mascot for a week is not fifty dollars of scope — we will say when it is a remodel versus more UV.