What is a 3D printing sprue and why is batch framing necessary?

In industrial 3D printing (SLS, MJF, SLA Resin), service bureaus like JLCPCB, PCBWay, and Xometry charge a per-part handling fee ($1.50 to $5+ per individual STL) because each part must be handled, cleaned, and sorted individually. Small loose parts also risk getting lost or damaged inside industrial depowdering stations and vibratory tumblers. A sprue groups multiple parts into a single connected production matrix with breakaway tabs, so the entire batch is recognized and quoted as 1 single part.

How do Sprue Generator's breakaway gates work without leaving surface marks?

Sprue Generator generates parametric conical gates with a tapered neck diameter (default 1.2 mm, adjustable from 0.6 mm to 2.4 mm). The narrow neck creates a deliberate stress concentration point at the exact contact surface, allowing parts to snap off cleanly with a twist or light flush cutter with zero surface scarring or pitting.

How does Sprue Generator prevent multiple-shell detection flags on JLCPCB 3D?

Online quoting systems inspect STL files for disjoint polygon shells. Sprue Generator executes real-time CSG (Constructive Solid Geometry) boolean unions that fuse the model vertices, gate cones, and runner frames into a single continuous, manifold, watertight mesh with zero internal self-intersections. This ensures the quoting algorithm classifies the model as one single solid entity.

Are my 3D STL files uploaded to any external server?

No. Sprue Generator processes all geometry, vertex parsing, CSG booleans, and binary STL exports 100% locally in your web browser using WebGL and Web Workers. Your CAD designs never leave your machine.

How does the automatic orientation algorithm minimize print time?

Sprue Generator analyzes all triangular facets of the imported STL, detects the largest coplanar surface cluster, and aligns that surface flat against the XY build plane. This minimizes the vertical Z-height bounding extent, which directly reduces the total number of sliced exposure layers and minimizes hydrodynamic peel forces in resin vats.

Which manufacturing services and materials are supported?

Sprue Generator outputs standard binary STL files optimized for all major manufacturing platforms including JLCPCB 3D Printing, PCBWay, Xometry, Shapeways, Craftcloud, and Protolabs across Resin (8001, 8228, Imagine Black), SLS Nylon (PA12, PA11), HP Multi Jet Fusion (MJF), and Metal SLM.

Sprue Generator — 3D Sprue & Batch Framing CAD Engine

Slash your 3D printing costs by 75%.

Stop paying per-part handling fees on small items. Sprue Generator automatically merges loose STL models into an industrial batch sprue with micro breakaway gates — billed as 1 single part by JLCPCB, PCBWay & Xometry.

Launch Studio with my STL

How It Works • Interactive CAD Demo Step 1 of 3

1 Import & Auto-Orientation

Drop any standard STL. The CAD engine computes the bounding box and automatically detects the largest planar surface to orient it flat on the build platform. This minimizes Z-height, accelerates resin curing time, and eliminates the need for support material on critical faces.

-75%

Part cost / 4

0.8 mm

Clean breakaway

100% Local

Zero file upload

Frequently Asked Questions

Why do online 3D printing bureaus charge per-part fees?

When you upload 20 separate files, technicians must individually label, wash, cure, inspect, and bag each piece. By fusing all parts into a rigid sprue matrix, the quoting algorithm and factory staff process it as 1 single component, cutting handling surcharges by up to 75%.

Will the breakaway tabs leave scars on my parts?

No. Sprue Generator uses tapered conical gates with a narrow neck (default 0.8 mm for SLA resin, 1.2 mm for SLS Nylon). This concentrates shear stress right at the interface, snapping off cleanly without surface tear-out or cratering.

Is my 3D CAD design private and secure?

100% private. All geometry calculation, 3D visualization, and STL binary generation run directly inside your web browser using WebGL and client-side memory. Zero files are uploaded to any server.

How does Sprue Generator prevent multiple-shell flags on JLCPCB & PCBWay?

Online quoting engines inspect STL files for disconnected polygon shells. Sprue Generator executes real-time CSG (Constructive Solid Geometry) boolean unions that fuse the model vertices, conical gates, and runner frame into a single continuous, manifold watertight STL with zero internal self-intersections, ensuring it is recognized as 1 single part.

What gate diameter should I choose for SLA resin vs SLS nylon?

For rigid UV resins (like JLCPCB 8001 White or Imagine Black), a neck diameter of 0.8 mm to 1.1 mm is ideal for effortless snap-off. For ductile SLS Nylon (PA12 / PA11) or HP Multi Jet Fusion (MJF), a neck diameter of 1.2 mm to 1.5 mm provides the perfect stiffness during bead-blasting and depowdering.

What license do I need to export STL files?

Sprue Generator is currently 100% free! You can design, orient, and export unlimited watertight production STLs at zero cost right now. In the future, STL exports will require a one-time lifetime license (€5) with free lifetime updates and commercial rights.