Mouse bites circuit board
Mouse bites in printed circuit boards are sections of the manufacturing panel that helps in assembling and fabricating circuit boards. Some individuals utilize the “mouse bite” term to describe and explain the over-etching of copper. However, what we mean here is different.
PCB manufacturers lay out circuit boards in a panel making use of CAM – Computer Aided Manufacturing systems. This panel ensures that the assembler and fabricator is given additional board material for any handling during all processes involved in manufacturing, which is very critical for the smaller boards.
Normally, panels have a uniform size, and you can lay out multiple instances of your printed circuit board design within the panel’s outline. The panel will not just make board manufacturing easier. It also allows the processing or multiple boards in panels for a similar cost as one board.
Once the fabrication, as well as assembly processes of these circuit boards, has been completed, then you must separate them from their panels. The process of separating them is known as depanelization. You can achieve the depanelization process either by breaking out the boards along the “V-grooves” or pre-scored lines, or cut them out.
The boards you have to break out have to be routed already around its outlines. This will help in bringing a separation between them and the panel, which are held by just small material tabs. The removal of the “breakout tabs” takes place, thereby making the board free from the manufacturing panel.
These tabs also feature small holes, which ensure the easy breaking of the PCB, and reduce the stress of the boards. With each of the tabs broken along the holes’ lines, the material remaining will have the appearance of a “mouse bite” until you have smoothed it out.
Mouse Bite PCB: Locations, Dimensions and Sizes
The holes utilized for breakout tabs may vary. However, majority of manufacturers utilize five holes in breakout tabs having these dimensions.
The hole size is usually 0.5 mm or 0.020 inch in diameter. Concerning the spacing, they are 0.76 mm or 0.030 inches apart.
The spacings and sizes of the mouse bite PCB holes appear random. This reduces the cleanup needed after the breaking out of the board from the panel. Though, it takes less effort for a smaller hole to smoothen out, it will also need more holes to be drilled and leave out much bulk material.
However, if there are too big holes, the board will end up having mouse bites that are larger and will need smoothening out. The hole placement within this breakout tab is important as well. The goal here is drilling them nearer to the PCB edge. This helps in reducing the tab material leftover that needs to be removed.
Constraints to consider during placement of breakaway Tab PCBs
There are some constraints to consider while performing the breakout tabs’ placement around the outline of the board.
Don’t make use of many tabs in order to save wear, effort, and time on its router bits.
Have enough tabs that can support the PCB board fully in its panel throughout the operations of PCB assembly.
Tabs having a minimum clearance of 0.125 inches should be located to the closest components.
Don’t place the tabs close to circuitry or sensitive components areas. This could cause the board to experience more breakout stresses.
At times, stress damages coming to the circuitry or components due to the tabs breaking may not be seen till later. It may also cause intermittent issues that won’t be debugged easily. This is why the location of breakout tabs, a distance away from any sensitive area, is very important to the circuit board’s success.
Also, if you don’t use enough tabs, and you don’t place them strategically to support your board during the manufacturing process, your board may end up flexing too much. This will prevent a reliable assembly. Now, this is the point where the experience and knowledge of your PCB manufacturer comes in.
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Any electronic enthusiast should have the ability to design PCB layouts if he is a pupil, an expert in the business, or a hobbyist. The construction of a proper PCB layout is an integral part of every PCB manufacturer. In this article, we'll show you the top 8 PCB Layout Design Tips for Total Beginners.
We should always keep the copper traces in mind while designing a Quick-Turn PCB Assembly! To manage a PCB trace’s resistance, we most commonly use weight, thickness, and width. Since you can't alter copper's physical properties, concentrate on the trace scale, which you can monitor.
To decide how thick and wide the traces should be for your use, use a PCB trace width calculator. Aim for a 5-degree Celsius increase in temperature. Always aim to use larger traces if you’ve got additional space on the surface!
It's also worth noting that traces on the exterior layers can cool down faster if the inner layers’ heat has to pass through copper layers before being done.
The simplest PCB Fabrication boards are those with copper tracks or interconnect on just one of their surfaces in this regard. One-layer PCBs are what they're called.
Small loops, incredibly high-frequency loops, should be kept to a minimum. Inductance and resistance are smaller in small loops. Inductance is further reduced by placing loops over a ground plane. Also, any PCB Prototype Manufacturer needs to create smaller loops as small loops minimize high-frequency voltage spikes caused by wide loops.
Small loops often minimize the sum of external signals that are experimentally coupled into the node or broadcast from the node. If you're building an antenna, this is what you want. For op-amp circuits, keep the loops short to avoid noise from being combined into the circuit.
To avoid shock risks in PCB Fabrication, generally, PCB manufacturers leave enough space between copper traces and fills. Since a solder mark isn't necessarily a reliable conductor, make sure there's ample room between them.
To maximize decoupling performance in PCB Prototype, place decoupling capacitors as close as possible to the integrated circuits’ power and ground pins.
Stray inductance is introduced as capacitors are positioned farther apart. Inductance is reduced by using several vias from the capacitor's hook to a ground plane.
Heat-sensitive components of the Quick-Turn PCB Assembly should be kept separate from heat-generating components. Thermocouples and electrolytic capacitors are two examples of heat-sensitive materials.
Placing thermocouples near heat sources can cause temperature readings to be inaccurate.
Electrolytic capacitors' working life will be reduced if they are mounted near heat-generating components.
Bridge rectifiers, diodes, MOSFETs, inductors, and resistors are examples of heat-generating components. The amount of heat produced is determined by the amount of current flowing through the components.
The layout ground in PCB Fabrication is not an ideal conductor, according to the rule of thumb. Make sure that all disruptive grounds are redirected away from any signals that require silence.
Build ground traces that are wide enough to hold the incoming currents. The impedance is reduced by placing the ground plane immediately under the signal traces.
When you're able to move on to the Quick-Turn PCB Assembly process, finish the final layout.
Make sure that all details about product procurement, assembly sketches, and Gerber files are correctly recorded. Remember that you're making a circuit board, and the success of the board is solely dependent on the production paperwork you make.
Heat can be transferred from one side of a PCB to the other using vias. This is particularly useful when a PCB is mounted on a heatsink on a chassis with additional heat dissipation capabilities. Heat is transferred more effectively via large vias than via small vias.
Many vias transfer heat more effectively than a single via, lowering component operating temperatures. Lower operating temperatures help better efficiency.
These were some of the tips to design your PCB Prototype Layout if you are a beginner! Now, you can develop your PCB layout designing skills by adopting the tips mentioned above. PCB HERO is one of the skilled PCB manufacturers for all your needs for PCB-related issues.
]]>As Gerber is the industry standard file type, It’s therefore easily recognized and processed by our manufacturing equipment.Export Gerber files form eagle may not be familiar to some of our clients.so we will proceed with a step-by-step description in the following section.
Generating Gerber Files
This guide assumes that you have finished designing your PCB within Eagle, and that you have a stored file in the .brd format. We must extract Gerber files from the .brd file using Eagle’s Cam Processor software. Steps for this extraction are outlined below:
and navigate to the .brd file that you would like to work with
as shown below:
from the top ribbon (highlighted below), or select File
-> Cam Processor
In this window, select Open -> Job, as shown:
This job file is set up for a 2-layer board, but the following examples show how to specify additional layers with the job if you are required. In the Output section of the Cam Processor window, select the File button, and navigate to the location in which you would like to store the converted Gerber files. Choose a file name for the layer, for example: the Component Side tab could have the file name “TopCopper.cmp”
we must use the Add button in the bottom-right corner of the window to duplicate one of the existing copper layers, and modify its settings.
then choose the copper layer that it represents from the scrolling list at the far right of the window. For a regular inner copper layer, you should only need to select the copper layer itself (Route2 in above picture), the Pads, and the Vias.
first choose the tab called “Drill PAD/VIA”, and ensure that the “Pads” layer and the “Vias”layer are selected (these are not selected by default). Also scroll down to ensure that the “Drills” layer is selected, although this one should be selected by default.
and scroll down in the layers list to ensure that both the “Drills” layer and the “Holes” layer are selected. (Holes is selected by default, but not Drills)
and scroll down in the layers list to ensure that both the “Drills” layer and the “Holes” layer are selected. (Holes is selected by default, but not Drills)
for each of the tabs within the Cam Processor window, select the Process Job button at the bottom of the window.
that you specified in step 7 to ensure that your Gerber files have been generated successfully. If you have access to a Gerber Viewer software, you can use it now to verify that the contents of your design files were preserved through the conversion procedure.
If you already have the Gerber files, and simply need to export your PCBs drill files on their own, then worry not! The process for this is actually quite straightforward; it incorporates only four (4) steps:
1. PCBWeb Designer
2. ZenitPCB
3. FreePCB
4. TinyCAD
5. Osmond PCB
6. BSch3V
7. ExpressPCB
8. Kicad
9. gEDA
10. Fritzing
11. DesignSpark PCB
12. EasyEDA
13. Ultiboard
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