Cast Text Legibility in Silicone Molds: Font Size & Stroke Width Rules

6 pt script on a chocolate bar mold fills with bloom in two pours - the text was never moldable at that stroke width on Shore A 35. RUUIPON builds custom silicone molds with logo and text at MOQ 50 and prototypes in 3-7 days. This guide sets font size and stroke minimums so cast text reads on the first production batch.

Quick answer: Minimum raised text stroke 0.5 mm (emboss into cast) or recessed 0.4 mm (deboss in mold face); font height ≥4 mm for food, ≥3 mm for resin. Pair with 2° draft on letter walls, 0.2 mm root radius, Shore A matched to material - vacuum degassed pour (~0.1% shrink) holds stroke within ±0.05 mm.

Text Legibility Minimums in One Table

Text type	Min stroke width	Min letter height	Best method
Emboss (raised on cast)	0.5 mm	4 mm food / 3 mm resin	Recess in mold cavity
Deboss (recessed on cast)	0.4 mm	3 mm food / 2.5 mm resin	Raise on mold face
Sans-serif (Helvetica-style)	0.5 mm	4 mm	Preferred - clean demold
Serif	0.6 mm	5 mm	Serif tips break below 0.6 mm
Script / cursive	0.8 mm	6 mm	Avoid for food logos

Emboss vs Deboss: Which Reads on the Cast

Terminology flips between mold and cast - define from cast part view on PO.

On cast part	On mold cavity	Visual on product	Demold risk
Raised text (emboss)	Recessed letters in cavity	Logo stands out - chocolate, soap	Low - material releases from recess
Recessed text (deboss)	Raised letters on cavity floor	Engraved look - resin, wax	Medium - peel across letter tops
Flush text	Not achievable	-	Requires two-part or insert

Chocolate logo depth pairing: logo depth guide. General logo limits: logo detail limits.

Font Size, Stroke Width & Spacing Rules

Thin strokes fill with cast material; tight letter spacing bridges ("H E L L O" becomes a blob).

Rule	Minimum	Notes
Stroke width	0.5 mm emboss / 0.4 mm deboss	Measure narrowest stem - not cap height
Letter height	4 mm food / 3 mm resin	Height = cap height sans descender
Letter spacing (kerning)	≥0.3 mm gap at narrowest	0.5 mm preferred on script
Line spacing	≥1.0 mm between baselines	Stacked taglines need 1.5 mm
Text depth (emboss)	0.4-0.8 mm into cavity	Deeper = sharper but harder demold
Draft on letter walls	2° minimum	3° on resin deep text
Root radius	0.2 mm	Sharp roots tear on demold - edge radius

Legibility Limits by Cast Material

Material	Min readable height	Min stroke	Shore A mold
Chocolate	5 mm	0.5 mm	Shore A 35-40 - chocolate Shore A
Gummy	4 mm	0.5 mm	Shore A 20-25
Epoxy resin	3 mm	0.4 mm	Shore A 30-35
Soap (CP)	4 mm	0.5 mm	Shore A 25-30
Wax melt	3 mm	0.4 mm	Shore A 25-30
Candle	4 mm	0.5 mm	Shore A 25-30

Contrast matters - dark chocolate on dark mold cavity hides text; test pour on sample is mandatory. Sample photos for approval: buyer sample photos.

Artwork Prep for Moldable Text

1. Vector only - AI/EPS/SVG; no raster logos for text strokes. Artwork prep.
2. Convert to outlines - expand fonts; we cannot use live type at CNC.
3. Offset stroke - if stroke <0.5 mm, thicken in artwork before quote.
4. Remove fine tm ® ™ - superscript marks below 2 mm height fail; spell out or enlarge.
5. Specify cast view - "emboss on cast face" on drawing eliminates flip errors.
6. One revision on stroke - included in prototype; production locks approved art.

Surface finish affects text read - matte cavity + gloss cast improves contrast. Surface finish.

Production Spec at MOQ 50

PO line	Example
Text	"BRAND" sans-serif emboss on cast - 5 mm height
Stroke	0.5 mm min; depth 0.6 mm recess in cavity
Draft / radius	2° walls; 0.2 mm root radius
Shore A	38 ±3 chocolate - locked at sample
Silicone	Platinum cure, vacuum degassed, ~0.1% shrink
Walls / spacing	2.5-5 mm walls, 8-20 mm cavity spacing
Sample	1 tray + chocolate test cast in 3-7 days

Send vector art with cast-view emboss/deboss callout to [email protected] | Contact RUUIPON | WhatsApp +86 135 3006 2969.

Frequently Asked Questions

Can you mold 2 mm tall text?
Technically yes on resin at 0.4 mm stroke - not readable on food; we flag sub-minimum art on quote.

Will text shorten mold life?
Yes - fine text concentrates stress; expect 20-30% fewer cycles vs plain cavity. Cycle life.

Mirror-reverse errors?
We proof art on sample photo before production - you confirm cast reads correctly.

Multi-line address blocks?
Each line ≥4 mm height; 1.5 mm line spacing - stack max 3 lines on food molds.

QR codes on molds?
Module width ≥0.6 mm; square modules only - test scan on sample cast.

MOQ with text molds?
MOQ 50 - text does not change MOQ; complex art may add 2-3 days to prototype.

Prototype lead time?
3-7 days - includes test cast with your material for legibility sign-off.