Solderpaste stencil
Photo Completed Stencil
Starting up the machine
Photo of LPKF ProtoMat machine:
Make sure the machine is turned on by pressing the on switch behind the machine on the back left.
Start by opening a specific file in the LPKFCircuitPro software titled "LPKF CircuitPro PM 2.7".
The software will go through the connection steps. Wait for these connections to complete.
If any maintenance windows pop up, select "Not performed yet".
Example of maintenance:
Choosing the correct template
A "New Document" window will pop up. This is where you will choose a project or a template. Head over to the "Templates" section.
The template we will be using is called the "Stencil for ProtoPrint S4". Click the template.
The software should now look something like this.
Head over to the "CAM view" tab in the top, you should see the stencil layout schematic.
Click the import button with the gold arrow at the top of the screen.
Import the solderpaste_top file onto the software. This is the stencil design that will be created.
After importing, change the Layer/Template drop-down menu to "SolderPasteTop". After selecting this, click "OK". You should now see your schematic in the CAM view.
Here is what your CAM view should look like.
Layout
Next, click the "Generate isolation and contour routing toolpath" button at the top of the software.
Change the material type to "Polyimide".
Change the copper thickness to "175 um" or whatever the thickness your sheet of Polyimide is.
Tools
Head down to the Primary drop down menu and select "Micro Cutter 0,1 mm". Luckily only the Micro Cutter 0,1 mm is needed for this process.
Then under "Available tools", uncheck the Universal Cutter 0,2 mm. Only the Micro Cutter 0,1 mm should be checked.
When done, press "Start"
Deleting toolpaths
If we head over to the Machining view, we can see that there is an outline in the stencil. We only want the purple part of the CAM view schematic to be cut, which is our stencil design. To remove the outer parts of the stencil, head over to "Toolpath" on the left side of the software.
Click the "Toolpaths" drop down menu and select the "Insulate_Perforation_Universal Cutter 0,2 mm" tab. This toolpath is the outline that we don't want to print.
Click "Delete selected object" using the red X at the top of the software.
From the same drop down menu, select "Insulate_SolderPasteTop_Micro Cutter 0,1 mm". The two layers' name are very similar. Click "Delete selected object" using the red X at the top of the software.
We should now be left with the pad outline itself and nothing else. The second layer we removed cut the outside parts of the orange. These cuts made the parts too close to each other, resulting in the solder paste over lapping, which we want to avoid. Keeping the inside allows enough stencil in-between cuts to allow space for the solder paste.
Placement
Right click the stencil design and move it to your desired place. To check if it fits, you can double click the orange parts on the board to move the laser to that point.
Processing
Head over to the Operate tab and selected "Process All". When ready, click the green arrow to proceed.
A "Processing Phase: MountMaterial" window will pop up. Make sure the stencil material is securely fastened onto the board using tape. Click "OK".
A "Material Settings" window will pop up. Double check that all the settings are correct and select "Continue"
Material thickness doesn't matter for the stencil unless you want to cut out the outline.
A "Placement" window will pop up. If you have already placed your board in the correct place, then click "Continue". If you have not, here is the time to do so.
A "Save document" window will pop up. If you want to save your stencil design, you can. Click "Yes" to do so and save it. If you want to simply print your stencil design, click "No".
Finally, a "Definition of machine area" window will pop up. You can choose to ignore this window by pressing "Cancel". This is skip the test of the tool cut width and start your design immediately.
Let the motor warm up, it should take about 3 minutes.
The cutting process should start now!
Cut out your new stencil using scissors! Make sure there is room around the stencil for the tape to secure it.
