Fanuc Robodrill G-Code Simulator

Verify the real Fanuc program — macros, subprograms, canned cycles, and all — before it runs

The Fanuc Robodrill earns its keep on high-volume small parts: a BT30 spindle up to 24,000 rpm, sub-second tool changes, and the Fanuc 31i control. And that's exactly the environment where programs don't come straight off CAM untouched. They're built from subprogram calls (M98/M99), driven by Macro B parametric logic, packed with Fanuc canned cycles, and routinely hand-edited at the control. Every one of those is a file your CAM never generated and can't reconstruct.

Eureka 3X Pro gives you a controller-accurate 3-axis digital twin of the Robodrill that reads the actual .nc program — macros, subprograms, and edits included — and proves it out before it reaches the spindle.

This page is about the 3-axis Robodrill (X, Y, Z). Eureka 3X Pro simulates 3-axis milling only. The Robodrill is often configured with a rotary table or 5-axis trunnion — see the scope note in the FAQ below.

What actually crashes a Robodrill (and why CAM never saw it coming)

The Robodrill's strengths are also where the risk concentrates. Because so much of a Robodrill program lives outside the CAM system, the failure modes below are the everyday ones:

Macro B parametric programs. Family-of-parts logic, IF/WHILE loops, variables that set depths and positions at runtime — this is the Robodrill's bread and butter, and it's written or edited by hand, not posted by CAM. A CAM simulator has no runtime to evaluate; it can't tell you where variable #100 actually drives the tool. A verifier that executes the macro logic can.

Subprogram calls (M98 / M99). A main program that calls subprograms by number, each repeated across a fixture of parts, is a Robodrill staple. If the CAM only knows the operations it generated, it can't follow the real program flow through every call and return. The verifier expands and runs the actual call structure.

Canned cycles (G81, G83, G73, G84…). Peck depths, dwell, retract planes, R-levels — the Robodrill is a drilling and tapping machine first, and canned-cycle parameters are where a crash or a broken tap hides. These execute on the control, not in the CAM's internal model.

Tool-length (G43 H) and work offsets (G54–G59). As on any Fanuc control, a wrong H number or the wrong active work offset drives the tool where the picture never showed. Geometry-based simulation misses it because it isn't a geometry problem.

Hand edits at the control. Given how much Robodrill programming is done and tuned at the machine, the pre-edit file your CAM simulated and the post-edit file the machine runs are often not the same program at all.

"But Fusion 360 already simulates my Robodrill"

It simulates the toolpath Fusion generated — and it's good at that. But the Robodrill runs a lot of code Fusion never produced. The distinction is the whole point:

Fusion simulates the toolpath it just generated. Eureka verifies the program that actually reaches the control.

The instant a program is a hand-written macro, a subprogram-driven main, or a file edited at the 31i control, it falls outside what a CAM-integrated simulator can reconstruct — it has no runtime to evaluate the parametric logic and no view of the edits. On a machine as macro- and subprogram-heavy as the Robodrill, that gap is wider than on almost any other 3-axis mill.

The full, fair breakdown: Fusion 360 Machine Simulation vs. Eureka 3X Pro →

Related Robodrill failure modes, in depth:

• Verifying parametric (Macro B) programs →
• Fanuc Robodrill post processor →
• G43 tool-length compensation crashes →

One post. The whole job crosses over automatically.

You don't leave Fusion, and you don't rebuild your setup in a second tool. The Eureka plugin — published in the official Autodesk Post Library for Fusion — is a cascade post: it runs automatically after your native Fanuc post, so Eureka verifies the real machine G-code the Fanuc post produced, not a reformatted copy.

And it carries the entire job across in one shot — automatically:

• the NC program (the actual posted code)
• the tools
• the work origins (your WCS / G54–G59)
• the stock
• the design model
• the fixtures

That's the difference between "import a file and hope your simulation setup matches reality" and the verification simply is your real Fusion setup. No manual stock definition, no re-entering offsets, no re-modeling the fixture — and therefore none of the setup errors that make a stand-alone simulator lie to you. The Fusion integration is included at no extra cost — you only need an Eureka subscription. For the code Fusion never generated — your hand-written Macro B routines and subprogram-driven mains — you open those in the twin directly. Being a native part of the Autodesk Post Library is why this isn't a leap of faith: it lives inside the Fusion ecosystem you already trust.

The Robodrill twin, at a glance

Because the twin executes the control's logic — not just the geometry — it follows the macros and subprograms the way the 31i will, catches the offset and canned-cycle errors before they reach the machine, and returns a cycle time from the real program. On high-volume Robodrill work, an accurate cycle time is a quoting advantage that compounds across every part in the run.

Why this pays for itself on a Robodrill

Two reasons, both sharper on a Robodrill than on a slower VMC. First, volume multiplies everything — a crash or a broken tap on a machine running thousands of small parts isn't one scrapped part, it's a stopped production run. Second, cycle time is money at volume — when tool changes are sub-second and parts are counted in the thousands, a program-accurate cycle time (versus CAM's optimistic estimate) is worth more than the subscription every time you quote.

This isn't an enterprise digital-twin platform with an implementation project and a contract. It's a focused verifier for 3-axis shops that a Robodrill programmer can be running this afternoon.

Try it on your worst Robodrill program

Take your most macro- and subprogram-heavy .nc — the one Fusion could never fully simulate — and run it through the Robodrill twin. That's the file that tells you whether this gap is real in your shop.

Eureka 3X Pro — 30-day free trial, no credit card required.

FAQ

Does Fusion 360 already simulate the Fanuc Robodrill? It simulates the toolpath Fusion generated, checked geometrically. It can't evaluate Macro B parametric logic at runtime, follow subprogram calls it didn't create, or account for edits made at the 31i control — and the Robodrill runs a lot of exactly that kind of code. That's the gap this twin fills.

Can it verify Macro B parametric programs? Yes. The twin executes the macro logic — variables, IF/WHILE, runtime-computed positions — so you can see where the program actually drives the tool, not just where a static toolpath would go.

Does it follow subprogram calls (M98/M99)? Yes. It expands and runs the real call structure — main and subprograms — so the verified program flow matches what the control will execute.

My Robodrill has a rotary table / 5-axis trunnion. Is that supported? No. Eureka 3X Pro verifies 3-axis milling (X, Y, Z) only — it does not simulate a rotary 4th axis or a 5-axis trunnion. If you run your Robodrill as a 3-axis machine, you're fully covered. Rotary and multi-axis work is outside this product's scope.

Which Robodrill models does the twin cover? The α-DiB5 family in S/M/L sizes running the Fanuc 31i control, in a 3-axis configuration. Exact travels depend on the specific model.

How do I connect Eureka to Fusion? Through a cascade post published in the official Autodesk Post Library for Fusion at cam.autodesk.com/hsmposts. It runs automatically after your native Fanuc post and hands the whole job to Eureka in one shot — NC program, tools, work origins, stock, design model, and fixtures — so the verification reflects your real setup with no manual re-entry.

Do I have to stop using Fusion? No. You keep posting from Fusion as usual; the cascade post runs after your native Fanuc post and passes everything to Eureka automatically. And any hand-written macro or subprogram main — the code Fusion never generated — you open in the Robodrill twin directly.

Is this an enterprise system? No. It's built for small-to-mid 3-axis shops — no implementation project, no contract. Start with a 30-day free trial, no credit card required.

Run every G-code program risk-free — before it touches your machine.