Design rules and user hints for the LPKF drilling and milling machine

1. Allegro layout

1.1 DRC

In general the DRC for the min line width has to be 4 mil, for the min insulation width it has to be 8 mil. In special cases, such as bond pads for chip on board layouts you can use 4 mil. This restriction is caused by the weak durability of the MicroCutter.

1.2 Etching shapes

To avoid floating copper areas use the allegro tool "shapes"

Process / Edit / Shapes	Select the shapes tool
Add Shape / Solid	Place the shape over the entire top or bottom layer
Void / Entire Shape	leave out all defined components of the layout
Fill	Fill the remaining shape

1.3 NcDrill

1.3.1 Plated holes:

If you need plated holes, you can only use hole sizes from 0.5 mm to 1.4 mm. The produced vias will be 0.3 mm smaller than the drilled hole. The pad where the vacuum needle is placed on must be about 0.4 mm bigger than the drilled hole. The table shows the inside needle diameters for the different hole sizes, which are equivalent to the needed pad sizes:

(Drilled) hole size:	min. Pad or needle diameter:
0.5 - 0.7 mm	0.9 mm
0.8 - 1.0 mm	1.4 mm
1.1 - 1.4 mm	1.6 mm

1.3.2 Tools

At the moment we got drills for hole sizes between 0.5 mm and 1.5 mm, with 0.1 mm spaces. Any hole size we can't directly drill and which is smaller then 1.5 mm will be drilled by the next larger tool. Hole sizes bigger then 1.5 mm will be made by an 1mm ContourCutter, which actually does not trill the hole, but it mills it.
Due to our unsuitable library, with unknown amounts of different hole sizes, now there is an Standard tool file with all hole sizes between 10 and 250 mil for platted and non plated holes. Here you can download the standard tool file nc_tools.txt in your project directory.
To use this file with the "nctape <name.brd>" Commandline command, you have to select 'Auto Tool Select'.

Process / Mfg / NcDrill
Param: AutoTool Select

To generate two different drill files, which are suitable for the import filter of CircuitCam. Select in the same Process:

Param: Separate platted/non-plated

The two files are ncdrill1.tap for plated and ncdrill2.tap for non plated holes.

1.3.3 Drill data offset

To avoid an drill data offset, following setups should be made:

Status / Drawing Size ... /	DRAWING EXTENTS Left X	0
"	DRAWING EXTENTS Left Y	0
"	MOVE ORIGIN X	free choice, but enter its negative values in Param: Offset X
"	MOVE ORIGIN Y	free choice, but enter its negative values in Param: Offset Y

1.4 Artwork

1.4.1 Aperture

These can be done automatically by Allegro therefor you have to select.

Process / Mfg / Artwork
Aperture / Edit ... / Auto (middle button)

1.4.2 Films

The following films can be imported automatically.

    Top*.*
    Bottom*.*
    Soldertop*.*
    Solderbottom*.*
    Outline*.*

2 Circuit Cam

This is the converter for the different Allegro output files.

CircuitCam is now installed on Achen. The Program can be started unproblematically via the net. The default project file is adapted to our Circuit Board Plotter.

You will find the Program at \\Achen\LPKF\CCAM\ccam.exe

The only problem is that each user at each PC has to unlock the program once. If you need the key just write a email.

2.1 Import of the Allegro files

All films (chapter 1.4.2), the two ncdrill files and the art_aper.txt must be imported.
Cause of the import filter you can choose all these files in the import menu and accept the questions afterwards.
Do not import nc_tools.txt file!

2.2 Convert data

Rubout
Define a rubout for both sides with an rectangular shape over the whole layout.

Contour Routing
Define Contour Routing with this setup

    Aussen
    Layer / BoardOutline
    Ergebnis-Layer / CuttingOutside
    Liste / LpkfCuttingTools
    Werkzeug / Contour Router 2.0 mm long
    Stegbreite / 2 mm

Gabs
Select, by clicking, the layer CuttingOutside in the layoutview and put in the middle of each side one gab. BE AWARE! It is very likely to alter the layersize by selcting the layer with the mouse! You can step to the next available point with the + and - keys.

Insulation job
Insulate both sides with the standard job.

The standard job work with two tools :
0.2 mm Universal cutter
1 mm Double edged Cutter

If you have smaller insulation width or an very large rubout then you must select an special job for each side with following command:

Bearbeiten / Isolieren /Job

Now select a suitable job,

ASIC micro Top Topside for layouts with insulation width smaller than 0.2 mm.

ASIC micro Bottom Bottom side for layouts with insulation width smaller than 0.2 mm.

ASIC rubout Top Topside for layouts with large rubouts.

ASIC rubout Bottom Bottom side for layouts with large rubouts.

ASIC micro rubout Top Topside for layouts which combines both problems.

ASIC micro rubout Bottom Bottom side for layouts which combines both problems.

and start it in the same window with

Start / Starten .

2.3 Export data

This must be done in the Layout window and all used layers must be visible, but do not select anything. This includes:

Insulated top & bottom, cutting outside, drill platted & non plated and soldermask top & bottom

3 Boardmaster

This is the control software for the plotter.

3.1 Tool library

Load the Tool library c:\lpkf30\data\ASIC.tol in Konfiguration / Werkzeug Bibliothek / Bohr Fraeskopf.

3.2 Material size definition

First you have to define the minimum (left front corner), then the maximum (right back corner).
You must keep in mind, that the depth limiter must be completely on the material and mustn't hit the tape strips.

3.3 Import the Layout

If you use the dispenser, than you can't use the whole material, this is caused by the offset between needle and tool. To ensure that your layouts can be dispensed, select a needle from the tool library. Then a white line will indicate your the max. usable material size if working with the dispenser.
Use the test structures to control the height of the universal and the micro cutter and also the test holes for the setup of the dispenser. They are in the directory c:\lpkf30\data.

struc0_1.lmp	Test structure for the Microcutter, insulation width 0.1 mm, line width 0.1 mm.
struc0_2.lmp	Test structure for the Universal cutter, insulation width 0.2 mm, line width 0.2 mm.

	Test holes for dispenser setup.
plated0_6.lmp	hole size 0.6 mm.
plated0_7.lmp	hole size 0.7 mm.
plated0_8.lmp	hole size 0.8 mm.
plated0_9.lmp	hole size 0.9 mm.
plated1_0.lmp	hole size 1.0 mm.
plated1_1.lmp	hole size 1.1 mm.
plated1_3.lmp	hole size 1.3 mm.
plated1_4.lmp	hole size 1.4 mm.

For the setup of the dispenser use your smallest hole, which must be platted .

3.4 Precautions while working with the plotter

The vacuum cleaner must work if you mill to get a proper board and not to allow toxic dust to be released unfiltered.
If you start the motor a tool must be in the spindle or the spindle will be destroyed.
Turn off vacuum when you refill the dispenser.
If you get the Error: "Spindelfehler", which can be caused by switching off the machine, while the Boardmaster software is up. You have to initialize the machine by opening the "Maschienenparamenter" box in "Konfiguration/Parameter" and selecting OK.

Good Luck

If you have questions or suggestion, please contact me.

last updated 99/03/15 by Ralf Achenbach .

ASIC micro Top	Topside for layouts with insulation width smaller than 0.2 mm.
ASIC micro Bottom	Bottom side for layouts with insulation width smaller than 0.2 mm.
ASIC rubout Top	Topside for layouts with large rubouts.
ASIC rubout Bottom	Bottom side for layouts with large rubouts.
ASIC micro rubout Top	Topside for layouts which combines both problems.
ASIC micro rubout Bottom	Bottom side for layouts which combines both problems.