What you’ll learn:
- How to make PCBs with a CNC machine.
- How to create PCBs using lasers.
- How to build multilayer PCBs using prototyping machines.
Printed circuit boards (PCBs) are found in almost all electronic devices. Typical PCB production uses etching to remove copper from a copper-clad board. Multilayer boards are formed by stacking multiple PCBs after they have been built. Rapid turnaround PCB services usually have turnaround times of days, but there are alternatives to in-house PCB creation.
LPKF provides two different kinds of “PCB printers.” The ProtoMat family uses computer-numerical-control (CNC) technology to remove copper from a board, while the ProtoLaser family leverages lasers. I recently had a chance to talk with Rory Grondin, Director of Sales – Americas at LPKF, about these platforms and how they work (see the video above). These are subtractive versus additive PCB printers.
Cutting Out PCBs with a CNC Machine
ProtoMat CNC machines work as you might expect (Fig. 1). They have a milling tool that grinds away the copper. A vacuum sucks the materials away from the board. The board is also held in place on a vacuum table.
The ProtoMat machine supports multiple bits, including drill bits to drill holes in a PCB. The system will automatically change the bits as required. Finer drill bits are needed for smaller holes down to 0.2 mm. The maximum speed of the milling spindle is 100,000 rpm.
There are desktop and large models with different characteristics and size limitations. Multilayer boards can be constructed in the normal fashion, one layer at a time. LPKF offers devices to manage this process and other PCB-related operations.
Prototyping with Lasers
ProtoLaser machines use a laser instead of a milling machine to remove material (Fig. 2). It performs this operation “a strip at a time”—it takes multiple passes to remove all of the copper from an area. It might seem like a tedious and time-consuming project, but the laser movement is very fast. The lasers are also very precise, allowing for extremely fine removal of materials both vertically and horizontally. The same type of vacuum support is used to remove materials from the work chamber.
The capabilities of the laser system are similar to the ProtoMat. They can handle single- and double-sided FR4 as well as single-sided RF, PTFE, and ceramic materials. Certain flexible substrates will also work with these machines.
PCB Production and Enhancement
Prototyping is an obvious use for these machines. They can churn on single PCBs or multiple varieties depending on the size of the board and the device involved. Boards can be created from scratch or existing PCBs can be modified. This will significantly reduce the turnaround time and work when customizing only part of a PCB.
PCB production is possible depending on the board’s complexity, the performance of the device, and so on. The systems excel in RF and fine feature applications where precision is required.
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