Electronics Production: PCB Milling

1. Core Machine Analysis

1.1 The Machine: Roland SRM-20

The Roland SRM-20 is a compact desktop CNC milling machine specifically designed for offices, laboratories, and educational environments. It is the standard equipment in FabLabs for fabricating high-precision Printed Circuit Boards (PCBs).

Process Type: Subtractive Manufacturing. Unlike 3D printing (additive), it removes material from a solid block. In PCB production, it mills away the excess copper layer to isolate conductive traces.
Key Specifications:
- Work Area: 203.2 (X) x 152.4 (Y) x 60.5 (Z) mm.
- Spindle Speed: Up to 7000 RPM, ideal for fine detail work.
- Resolution: 0.01 mm / step (mechanical resolution), ensuring precision for Surface Mount Device (SMD) components.
Design Features:
- Full Enclosure: Prevents dust from spreading and reduces noise, ensuring safety.
- Dust Collection: A slide-out tray at the bottom collects copper and substrate debris for easy cleaning.

1.2 The Software: VPanel for SRM-20

VPanel is the dedicated control software for the SRM-20. It acts as the "cockpit" between your computer and the machine. It does not generate toolpaths (CAM software does that); it only executes them.

Coordinate Systems:
- Machine Coordinates: The absolute, fixed position of the machine spindle (cannot be changed).
- User Coordinates: The most important system! We use "Set Origin" to define the starting point (X/Y/Z Zero) for our specific job.
Key Functions:
- Move: Controls the spindle movement along X, Y, and Z axes (supports continuous or step movement).
- Set Origin:
  - XY Origin: Defines the bottom-left corner of your PCB design on the material.
  - Z Origin (Critical!): Defines the exact height of the tool tip relative to the material surface. Setting this too low breaks the bit; too high results in no cut.
- Override: Adjusts spindle speed and feed rate percentages in real-time during operation to fine-tune cutting quality.

2. Market Landscape: Comparable Devices

Besides the Roland SRM-20, there are several other common desktop CNC machines used for PCB production.

2.1 Bantam Tools (Othermill)

Origin: USA.
Features: Excellent software experience with automatic conductive probing for material location and tool length detection.
Pros: Faster than SRM-20, very easy tool changes, high software integration.
Target: High-budget labs requiring premium user experience.

2.2 LPKF ProtoMat (Industrial Grade)

Origin: Germany.
Features: Industrial-grade PCB prototyping.
Pros: Extremely high precision, chemical-free process, integrated vacuum, capable of through-hole plating for multilayer boards.
Cons: Extremely expensive (5-10x the price of SRM-20), high maintenance.

2.3 Genmitsu 3018-PRO (Entry Level)

Origin: China.
Features: Open-source architecture (GRBL), extremely affordable.
Cons: Poor rigidity, high spindle runout, difficult to mill fine traces (< 0.2mm), requires significant modification.
Target: DIY hobbyists and makers on a strict budget.

3. Comparison Matrix

Feature	Roland SRM-20	Bantam Tools	Genmitsu 3018
Price	Mid-Range ($$)	High ($$$)	Very Low ($)
Precision	High	Very High	Low/Mid
Ease of Use	Good	Excellent	Hard (Steep learning curve)
Software	VPanel (Simple Control)	Bantam SW (Full Feature)	Candle/GRBL (Open Source)
Target User	FabLabs / Schools	Pro Engineers	DIY Hobbyists