Modifying a keyboard PCB is often necessary for custom mechanical keyboard builds, whether to fit a specific case, adjust its size, or create a unique layout. However, cutting a PCB requires precision to avoid damaging essential traces, components, or layers within the board. Using the right tool not only ensures a clean and accurate cut but also minimizes the risk of electrical issues or PCB failure.
There are several tools available for cutting a keyboard PCB, each with its advantages depending on the complexity of the modification. Whether you’re a hobbyist or an experienced builder, understanding the proper cutting techniques and safety measures is crucial to achieving the best results. This guide What Tool to Cut Keyboard PCB? will cover the best tools for the job, step-by-step cutting instructions, and important safety precautions to keep in mind.
Manual Cutting Tools
Manual cutting tools offer a simple, low-cost option for cutting PCBs and can provide good control for detailed work. However, they require more physical effort and may not produce perfectly clean cuts.
Snips/Flush Cutters
Snips or flush-cut pliers are ideal for making small cuts or trimming leads on a PCB. Look for models with precision ground edges and a flush-cutting face to avoid deforming the board. These tools work well for clipping component leads close to the board on a populated PCB.
Scoring Tools
Scoring tools like metal rulers or specialized scoring knives allow you to cut a PCB by first scoring along the desired line and then snapping the board apart. This method works best for isolating larger sections from a bare PCB. Apply firm, even pressure when scoring to avoid cracks traveling off the scoreline.
Utility Knives
A good utility knife can be used to cut sections out of thinner PCBs. Be sure to secure the board to prevent slippage and use a sharp blade for a clean cut. Utility knives offer good control but can be difficult to use for intricate cutouts. Repeatedly score along the cut line rather than trying to cut through in one pass.
Power Cutting Tools
Power tools offer increased cutting speed and precision compared to manual options. However, they require more safety precautions and control to avoid damaging the PCB or components.
Rotary Tools (Dremel)
Rotary tools like the Dremel are excellent for cutting detailed shapes and curves into PCBs. The high-speed cutting bits provide very clean cuts with minimal debris. Rotary tools are also useful for cutting out areas around components on a populated board.
Using a rotary tool takes practice to maintain control and avoid overcuts. Go slowly, make multiple light passes, and keep the tool perpendicular to the board surface. Secure the PCB firmly before cutting. Always wear eye protection when using high-speed rotary tools.
Jigsaws
A jigsaw allows for straight cuts through a PCB quickly. This power saw is best suited for separating larger boards into smaller sections along a straight line. Jigsaws rapidly cut through the board thickness.
Proper clamping is crucial when using a jigsaw on PCBs to prevent shifting during the cut. The narrow jigsaw blades produce very little debris. However, the cutting action can potentially damage components if not careful on a populated board.
Guillotine Cutters
Guillotine-style PCB shears utilize a pivoting blade to slice cleanly through boards in one pass. These specialized tools ensure a straight, perpendicular cut with minimal deformation along the edges.
Guillotine cutters work best on bare boards up to a certain thickness. Trying to cut through large components will cause issues. The cutting area is limited by the throat depth of the tool. Higher quality guillotine cutters allow for very precise and repeatable right-angle cuts.
Laser Cutting for PCBs
Laser cutters are a precise and clean method for cutting keyboard PCBs, offering intricate cuts and shapes with tight tolerances. They are non-contact, eliminating the risk of tearing or deforming the PCB material. Laser cutting also leaves a clean edge with no burrs or rough surfaces, minimizing the need for post-processing and cleaning.
It can make cuts close to components without risk of damage but must be cautious not to expose sensitive electronics. However, laser cutters have limitations, such as cutting through PCB materials up to a certain thickness and having small bed sizes. Larger-format laser cutters may be required for full keyboard plates or cases, increasing equipment costs. Despite their advantages, high equipment costs make laser cutting less accessible for personal projects.
Types of PCB Cuts Needed
When building custom keyboards, you’ll likely need to make a variety of different cuts to the printed circuit boards. Here are some of the most common cut types:
- Straight Line Cuts: Many keyboard cases, plates, and even some controller boards require simple straight-line cuts. This could involve trimming the PCB to a specific size or separating sections of the board. Straight cuts allow clean edges and precise dimensions.
- Detailed Shape Cuts: For unique case designs or non-rectangular keyboard layouts, you may need to cut intricate shapes out of the PCB material. This could include curves, notches, or even holes for components or mounting hardware. Precision cutting tools are required for these detailed outlines.
- Scoring and Snap Cuts: Some PCB materials allow you to score along a cut line and then snap the board along that score for a clean break. This scoring technique can create nice straight edges, especially for larger cut sections. However, it requires PCBs made of the right materials that will snap cleanly.
Recommended Tools for Keyboard Parts
For cutting keyboard plates, guillotine-style shear or heavy-duty snips are recommended. These allow for clean, straight cuts through the thin metal plates. Avoid using tools that could bend or deform the plate material.
When trimming keyboard cases, rotary tools like a Dremel are very useful for cutting out precise shapes and openings. The various burr bits give you control for detailing the case to fit components. For simple rectangular cases, a jigsaw can make straight cuts efficiently.
Controller boards are often made of more rigid FR4 material. Scoring tools that let you snap the board along a scored line work well here. A sharp utility knife can score deeply enough for a clean break. Smaller sections can be cut out using flush snips.
For any cutting of populated boards with components installed, a pair of precise flush cutters is essential. These allow you to snip off component leads cleanly without damaging the board. Go slowly and don’t twist to avoid ripping pads off.
Laser cutters provide unmatched precision and quality for cutting keyboard parts from flat materials like plates, cases, and unpopulated boards. The laser can easily cut out complex shapes and openings. However, laser access may be limited for some DIYers.
Step-by-Step Guide to Cutting a Keyboard PCB
Cutting a keyboard PCB requires careful planning, precision, and the right tools. Here’s a step-by-step guide to help you make clean, accurate cuts:
Preparation
Before cutting, ensure you’re working in a well-lit, clean, and stable workspace. Secure the keyboard PCB to prevent it from shifting during the cutting process.
- Mark the Cut Line: Use a fine-tip marker or pencil to mark the exact line where you intend to cut. Ensure this line is straight and follows the desired cutting path.
- Protect Surrounding Components: If necessary, cover sensitive areas (like key switches or circuits) with painter’s tape to prevent accidental damage.
- Wear Safety Gear: Always wear protective eyewear and gloves to safeguard against debris, flying particles, and sharp edges.
Choosing the Right Blade or Bit
Select the appropriate blade or cutting disc based on the tool you’re using. For rotary tools like a Dremel, use a fiberglass-reinforced cutting disc. For hacksaws, a fine-toothed blade designed for metal or plastic is best.
- Rotary Tool: Use a small, fine-cutting disc for precision.
- Hacksaw: A metal cutting blade with fine teeth will offer the best result.
Cutting Process
Now it’s time to make the cut. Follow the instructions specific to your tool to ensure a smooth and accurate cut.
- Rotary Tool: Start the tool at a slow speed and guide the cutting disc along the marked line. Move in small, controlled motions, allowing the disc to do the work. Avoid pressing too hard to prevent the tool from skipping.
- Hacksaw: Align the blade with your marked line and slowly start cutting with even pressure. Let the saw do the work without forcing it, maintaining a steady rhythm.
Sanding and Finishing
Once the cut is complete, you’ll likely need to smooth out any rough or sharp edges to prevent future damage or shorts.
- Use Sandpaper: Start with a medium-grit sandpaper (around 400 grit) and gently sand the edges to smooth out rough spots.
- Inspect the Cut: Make sure the edges are even and clean. If any rough sections might cause electrical issues, continue sanding until they’re smooth.
Test the PCB
After cutting and finishing the edges, it’s important to test the PCB to ensure it still functions properly.
- Inspect for Damaged Traces: Look for any broken or exposed traces where the cutting tool may have made unintended contact.
- Check for Shorts: Use a multimeter to test for continuity and ensure there are no electrical shorts caused by cutting.
Final Adjustments
If the PCB requires any additional modifications, such as repositioning components or re-soldering certain areas, make those adjustments after the cutting process is complete.
Avoiding Component Damage
When cutting a populated PCB with surface-mount components installed, extra care must be taken to prevent damaging the delicate components. Here are some tips for safely cutting around components:
- Covering Components: One of the best ways to protect components is to cover them with tape or a thin protective film before cutting. Masking tape or Kapton tape works well for this. Carefully apply the tape over the components, ensuring they are fully covered and secured.
- Slow, Careful Cuts: Never try to cut through a populated PCB quickly. Take your time and make slow, controlled cuts. Go slowly when the cutting path nears components, lifting the tool up and over them if needed. Making multiple light passes is better than trying to cut all the way through in one go.
- Lead Clipping: For through-hole components with leads on the PCB, use a pair of flush-cut pliers or snippers to carefully clip the leads flush with the board surface. Do this before attempting any board cutting to avoid putting stress on the components during the cutting process.
Safety Considerations
Safety should be the top priority when cutting PCBs, especially with power tools involved. Proper personal protective equipment (PPE) like safety glasses and cut-resistant gloves is essential to protect your eyes and hands from flying debris or accidental blade contact.
Always secure the PCB firmly to your workbench or cutting surface before making any cuts. A stable workpiece minimizes the risk of the board shifting unexpectedly. When using power tools, keep the cutting path clear and avoid positioning any part of your body in line with the blade. Power tools should only be operated with two hands for full control.
Remove any loose items like jewelry or loose clothing that could potentially get caught in the cutting tool. Maintain a clean, uncluttered workspace to prevent tripping hazards. Never operate power tools when tired or impaired. Taking proper precautions allows you to cut PCBs safely.
FAQs
Can I cut a keyboard PCB without damaging it?
Yes, with the right tools, careful preparation, and technique, you can cut a keyboard PCB without damaging it.
What is the best tool for cutting a keyboard PCB?
A rotary tool like a Dremel is best for precise cuts, while PCB shears are ideal for clean straight cuts.
Can I avoid cutting the PCB altogether?
Yes, using a smaller PCB design or modular keyboard PCBs can eliminate the need for cutting.
How can I prevent overheating the PCB while cutting?
Use low-speed settings on rotary tools and make multiple light passes to avoid excessive heat buildup.
What safety precautions should I take when cutting a PCB?
Always wear safety goggles and a mask, and ensure proper ventilation to protect from dust and debris.
Conclusion
In conclusion, selecting the right tool for cutting a keyboard PCB is essential for achieving clean, precise modifications. Whether using a rotary tool for detailed adjustments or PCB shears for straight cuts, each tool has its ideal use case based on the type of cut and precision needed. Always prioritize safety by wearing proper protective gear and working in a well-ventilated area. Remember, practice on a scrap PCB before modifying your actual keyboard to ensure you get the hang of the process. Taking these precautions will help you create a functional and customized keyboard without compromising its performance.
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