LPKF Standard Operating Procedure

Overview

The LPKF ProtoMat PCB milling tool is intended for milling structures onto copper-coated circuit board materials for in-house production of single or double-sided PCBs.

Tool Parts

Nanofab-supplied copperboard

The Nanofab supplies copperboard for free, non-bulk use. We offer:

• P/N US-106394, FR4 9"x12" 1/2 oz copperboard has 0.059" thickness. Copper 18um
• P/N US-106397, FR4 9"x12" 1oz copperboard has 0.059" thickness. Copper 35um

Tool bit color schema

• Red = MicroCutter
• Orange = Universal Cutter / Universal Milling Tool
• Purple = End Mill
• Blue = RF End Mill
• Green = Drill Bit / Spiral Drill
• Yellow = Contour Router (the sides of these cutters look knurled but are sharp)
• Yellow-Green = Long End Mill

Standard Operating Procedure

Worktable preparation

1. Ensure that the stage is clean, and the vacuum to clean any dust or particles inside the enclosure.
2. Use the inspection mirror on a handle to look at the tips of the bits. Clean off any debris and check for broken bits. If you are not sure if a bit is in good shape you can use the nearby microscope.
3. Turn on the system exhaust under the table. An LED should indicate the system is on.
4. Ensure the white plastic perforation board is flat and not too scarred from previous processes. If it cannot lay flat, or PCB cannot lay flat on top of it, then replace the perfboard using one of the extras found in the supplies on the table.
5. Mount the board onto the stage using tape, taking care to ensure that board is flat and secure against the stage.

System startup and design file import

1. Lift the hood and turn on the machine through the power switch located on the side of the stage. Keep the hood closed afterwards for the machine to initialize when starting the software.

   

2. Login to the computer with the username and password posted on the tool computer.
3. Double click the LPKF CircuitPro software.

   

4. If you are not presented with a "Connection steps" dialog and an initialization sequence which starts with machine connection, and ends with machine referencing and camera connection, then select from the top menu "Machining" > "Connect" to attempt the connection an initialization.
5. You may see a prompt asking to judge the wear and tear on the working depth limiter. Because the one we have fitted is made of brass and not plastic, it is not subject to excess wear and you may confirm the dialog.
6. After initialization, the software will ask for either an existing CircuitPro project (.cbf) or to load from one of the existing templates.

   

7. If creating a project for the first time, click Load default template or load from the existing template list. If a project file exists, click Open project... load the appropriate file and proceed to step 7.
8. If a design already exists, the Gerber files are ready to be imported, and the template layers are unneeded, delete all template layers by selecting all layers and clicking delete layer.
9. To import and add existing Gerber files and Drill files to the project, click File > Import or press Ctrl + I. An Import window will appear. Press OK to import the files. A warning stating new layers were created will appear. Press OK.
10. For each layer, select the appropriate Phase (to determine when the layer is going to be cut) and Tech (what the layer corresponds to). See the reference table below.
11. Unselect or delete Silk Screen or Solder layers.

Layer assignment

Name This may vary depending on what software was used to create the design files. See AllAboutCircuit's article on some common naming conventions.	Tech	Phase	Purpose
Fiducial	Fiducials	DrillFiducial	These holes will be placed outside the PCB pattern area, providing a reference for the tool after the user flips over the copperboard to mill the other side.
DrillPlated	Drilling	DrillingPlated	The mill will first drill these holes, and then prompt user to remove the PCB and electroplate it, coating the via interiors.
DrillUnplated	Drilling	DrillingUnplated	The mill will drill these holes after the user has been prompted to remove the PCB and electroplate, if applicable.
TopLayer	Wiring	MillingTop	Shallow surface milling to cut PCB traces
BottomLayer	Wiring	MillingBottom	Shallow surface milling to cut PCB traces
SolderPasteTop	Solder Paste	Dispense
SolderPasteBottom	Solder Paste	Dispense
SolderMaskTop
SolderMaskBottom
SilkScreenTop
SilkScreenBottom
BoardOutline	Mechanical	ContourRouting	The border of the PCB, that will allow removal from the surrounding copperboard once cut. Sometimes called the "profile"

Create Fiducials

1. If your file does not have a Fiducial layer, click Insert > Fiducial >  Create new layer. If it does have a layer already, click on the Cam View tab, then click on the menu item Insert > Fiducial > Fiducial.
2. Place fiducials by the four corners of the profile by entering specific coordinates in the Create fiducial window before clicking Apply or by clicking where the fiducial will be placed under CAM view. Ensure you select “Relative to anchor point.” 
3. If you do not like where a fiducial was placed, you can right click it and press Delete.
4. Press Close when you are done placing fiducials.
5. Set the Phase of the Fiducials layer to DrillFiducial.

Generate Toolpaths

1. Click Machining > Connect. Check that the software is connected to S103.
2. Click Generate isolation and contour routing toolpath.
3. Under the Isolate tab:
   • Set the material type and the copper layer thickness depending on the copper layer you are using. For a deeper cut, it is recommended to input a value 1 to 2 ums thicker than the copper layer used. Also set the Isolate and Contour Routing depending on the specifications of the design.
   • Select the isolation / rubout level by clicking on the big left and right arrows
   • Make sure all bits in the "Available tools" are checked so that the Toolpath generator can use them.
4. Under the Contour routing tab:
   • Select the type of contour cutting you want (tabs remaining around your PCB before you pop it out of the whole substrate)
5. Click Start.
6. Resolve any Warnings. For processes with no available tools, assign the toolpath to an appropriate alternate before clicking Calculate.

Cutting

1. Prepare the worktable:
   1. Ensure that the stage is clean and the board is bent flat.
   2. Use the vacuum to clean any dust or particles left inside the LPKF.
   3. Mount the board onto the stage using tape, taking care to ensure that board is flat and secure against the stage.
      • Note that the copperboard side currently facing up is considered the "bottom."
2. Click the button with hover text “Open the dialog to edit the contents of the tool magazine.”
   1. Check that all the required tools are slotted in the LPKF.
   2. Inspect all bits with a mirror and clean or replace bits as needed.
   3. If the toolpath generator has assigned bits that are not available to you, you can remove them from the active list via Edit > Tool Library and click on the bits not available and then click "Remove tool." Then regenerate your toolpaths.
3. Make sure the hood of the LPKF is closed before clicking Start the Board Production Wizard.
4. On the Material Settings window:
   1. Click “Select the camera head as active head.” Click anywhere on the substrate in the Machining View tab to place the camera over the substrate and then click “Autofocus.” Wait for the autofocus procedure to complete.
      • If the camera shows no image, read the troubleshooting section below.
   2. Clicking in the Machining View pane will move the camera head to the location on the worktable that you clicked. Use this method to bring the bottom left corner of the PCB into the center of the camera view.
      • You can also use the arrow keys under X/Y positioning to move the camera. Good focus from the prior step is required.
   3. Once the bottom left corner of the PCB is centered on the camera, click the icon in the Material Settings window that shows a bottom left corner with a circle around it. This "teaches" the machine where that corner is.
      • If the PCB is poorly placed, the bottom left corner might tell you it is at an inaccessible location. If that occurs, close the Wizard and reposition the board.
   4. Repeat the above steps for the top right corner of the PCB.
5. In the Placement step, you adjust the placement of the cut on the copper board. You can click and drag the design around the board on Machining View.
   • In the Machining view, click and drag the design where you want to cut it out within the bounds of the orange bordered copperboard.
   • The dX and dY values place the top left corner of the design relative to X=0 and Y=0.
   • If you have pre existing cuts on the board to avoid overlapping, first move the design to the lower left corner of the copperboard representation and read the coordinates off of the Placement dialog. You can now use a ruler on the physical copperboard to calculate coordinates for the location you want to put the design.
6. The wizard will continue, doing the DrillFiducials, Marking Drills, and the Drilling Plated steps.
   • Immediately before performing the first cut, if the tool hasn't been used in a few hours, the spindle will insist on warming up for up to about 16 minutes. If the tool was used recently, there may be only a short warmup or no warmup.
   • The tool will make these marks treating the upwards surface of the PCB as the "bottom."
7. Dismount Material and Through-hole Plating steps:
   • Remove the PCB and electroplate it if needed.
   • If you will not be doing electroplating, then you may disregard the instruction to remove the workpiece and keep it where it is.
8. ReadFiducial step
   1. Because the tool assumes you removed and replaced the substrate, the ReadFiducial step is next so the tool can reference to the substrate features.
   2. The camera will first autofocus before confirming if the image is sharp.
   3. It will attempt to locate the first fiducial. It may not be successful, but if it is successful and the yellow circle overlaps perfectly with the camera image of the fiducial, then you can click Accept Current Position and it will proceed to the other fiducials.
   4. If the fiducial couldn't be found or the fiducial-on-camera-to-yellow-circle alignment isn't perfect, reposition the camera using the arrow buttons under the X/Y positioning section of the Processing pane. Make sure the step size is appropriate (1mm for searching, 0.005mm for finest adjustment) until the fiducial is centered in the yellow circle overlay on the camera. Click Accept Current Position for each fiducial once it's well aligned.
      • The fiducial read ordering is: bottom left, bottom right, top right, top left. You will need to follow this order if the software cannot figure it out.
9. "The Milling bottom layer" step will cut any patterns on that layer.
10. On the "Flip material" step, open the hood and flip the board towards you or away from you before mounting it with tape. Do not flip the board sideways.
11. The "Milling top layer" step will cut any patterns on that layer.
12. The "Drilling unplated" step will drill any holes on that layer.
    • If you performed electroplating earlier, doing this drilling now will of course leave those new holes unplated.
13. The "Contour routing" step is the last step in the process, and will cut out the border of your design.
14. When the process finishes, unload the copper board and use the vacuum to clean the dust.
15. Close the CircuitPro Software - this will allow the milling head to move to a safe location. If this is not done and the tool is powered off manually before closing the software, the milling head will drop to the bottom of its Z axis while above the cutting table and is likely to break whichever bit it happens to be holding.
16. Confirm the milling head is in a safe location (above one of the magazine tool slots in the upper left or upper right)
17. Turn off the LPKF power switch (the milling head will quickly drop) and close the hood.

Solder dispense

1. After your board is fully manufactured, make sure your project is open and has the same fiducials as when the board was cut.
2. From the top menu, select Wizards > Dispense Preparation Wizard.
3. The wizard will prompt as follows, with photos:
   1. "Prepare dispenser": Remove solder syringe from refrigerator, let warm to ambient temperature, and install onto the dispenser unit, which is not installed on the tool.
   2. "Mount dispenser": Install a pink plastic dosing needle to the solder syringe. Connect the pressure hose to the dispenser (on a new solder syringe, this will displace some solder, be prepared to catch it with a cleanroom wipe). Mount the dispenser to the holder and connect the temperature sensor.
   3. "Mount auxiliary board": take a small copperboard, measure the thickness, provide it to the wizard, and tape it on the table out of the way of any areas to be dispensed.
      • We need one of these

Troubleshooting

Symptom

Solution

The software reports the camera cannot connect, or the camera display is all black, or you get a popup reading "CLPKFGrabberBase: InitGrabber UEyeGrabberNew failed!"

Check that the PC correctly recognizes the camera: Open the Start Menu, search for and open IDS Camera Manager Look for a device with the model name "XS." If you cannot get the "XS" device to appear: Acknowledge any error popups in CircuitPro. Do not click "Retry." Close the CircuitPro software. Power off the LPKF S103 using the power switch. Reboot the PC. Repeat the IDS Camera Manager check. When the "XS" device appears in IDS Camera Manager, that indicates the camera connection to the PC is good, and it is the CircuitPro software that is having a problem. Acknowledge any error popups in CircuitPro. Click "Retry" if that is currently an option. If that is not an option or that fails, proceed. Close the CircuitPro software. Power off the LPKF S103 using the power switch, wait 1 minute, power back on. Re-check that "XS" is listed in the IDS Camera Manager. Open the CircuitPro software and hope the camera connects. If not, you can keep restarting the software and the tool power.