**Question:** When mass-producing PCB boards, cutting irregularly shaped boards has always been a challenge—either the edges are uneven or the dimensional tolerance is too large, causing them not to fit into the casing. I've heard that CNC routing machines are the key to solving this problem? What are their advantages compared to ordinary punch presses?

**Answer:** This question hits right on point! Cutting irregularly shaped PCBs (like round, arc-shaped, or boards with card slots) is a persistent headache in mass production. Ordinary punch presses rely on molds for cutting, which are not only costly but also lack precision. In contrast, CNC routing machines are the "magic tool" for mass-cutting irregular PCBs, capable of controlling dimensional tolerances within **±0.05mm** and producing edges as smooth as a mirror.

Two years ago, we received an order for a smart home PCB—an irregularly shaped board with three arc-shaped card slots that needed to perfectly match the casing. Initially, we worked with a factory using punch presses. The mold cost 5,000 RMB, but the mass-produced boards had two major issues: First, the card slot positions were misaligned, with a maximum deviation of 0.15mm, preventing them from fitting into the casing. Second, the edges had chipping, requiring manual polishing, which significantly increased labor hours. Later, we switched to a larger factory equipped with CNC routing machines. No molds were needed—they simply imported the Gerber file, and the batch-cut boards were dimensionally precise with smooth edges, achieving a 100% casing fit rate while also saving on mold costs.

**Three core advantages of CNC routing machines:**

**1. No mold required, flexible adaptation to irregular designs**  

Cutting PCBs with punch presses requires creating molds first—designing and producing the mold can take days or even weeks, with costs ranging from thousands to tens of thousands of RMB. Once the mold is made, it cannot be modified. If the design changes, the mold becomes useless. CNC routing machines eliminate the need for molds entirely. Simply import the PCB outline Gerber file into the system, and the machine’s CNC router bit automatically cuts according to the pattern. Whether it’s round, arc-shaped, or complex irregular designs, it can handle them effortlessly. For small-batch, multi-variant orders, this is a "godsend"—not only saving on mold costs but also shortening the production cycle.

**2. Ultra-high precision, dimensional tolerances controlled at the micron level**  

Punch press cutting depends on mold precision, and the press undergoes elastic deformation under force, leading to dimensional deviations. In contrast, CNC routing machines use high-precision servo motors to drive the router bit, with positioning accuracy reaching ±0.01mm and cutting accuracy achieving ±0.05mm. For example, when producing a round PCB with a required diameter of 50mm±0.05mm, using a CNC routing machine for batch cutting resulted in a diameter deviation within ±0.03mm for all 1,000 boards. With a punch press, the deviation could reach ±0.2mm, far from meeting the requirement.

**3. Smooth edges, no chipping or burrs**  

If the edges of an irregular PCB have chipping or burrs, it not only affects appearance but can also cut hands or cause poor casing assembly. Punch presses exert force on the substrate during cutting, making chipping likely. CNC routing machines, however, use "rotational cutting" with a router bit, ensuring a stable cutting process and smooth edges that require no additional polishing. Even more impressively, high-end CNC routing machines come with a "chamfering function"—automatically chamfering the PCB edges to prevent sharp edges from damaging component leads or injuring operators.

**Here’s my advice:** For mass PCB production, if you’re dealing with simple rectangular boards, punch presses are fine. But for irregularly shaped or high-precision boards, always choose a manufacturer equipped with CNC routing machines.