Kress CNC Portal Mill

MachineInfoBox Kress CNC Portal Mill
Type:	CNC Mill
Material:	wood, metal
Used with:	endmills
Location:	Hot Metal Area
Access Requirements:	CNC Mill Introduction
Status:	Working
Manual:	Manual of the Controller Board
Tutors:	Luzian Sebastian
Similar (More or Less):	CNC router

Introduction

This CNC portal mill was bought used in 2022 from a maker that build and used it to machine aluminum parts for other CNCs. Main features and specs:

• Portal Mill driven by 3 stepper motors (23HS30-2804S)
• 80kg steel & aluminum build, t-slot table
• Spindle: 800w China HF spindle with ER11 collet
• Work area: 300x360x80mm
• Controller: SMC5-5-N-N with jog-wheel
• Power Supply: Meanwell 48V 10A
• Stepper Drivers: 3x Leadshine DM556

CAD / CAM

The SMC5-N-N-5 processor uses the "mach3" post processor. The one included in Fusion 360 is reported to sometimes cause erratic behavior with this controller. For Fusion 360 in a new set-up, import the machine file from Github. Edit the machine settings. Under "post processor", import the post file. Make sure to save the post under "local".

If you are using FreeCAD simply export your gcode as mach3.

Machine Control

Powering on

The machine itself is mainly operated by the control panel located on the right side of the machine box and the jog-wheel (SMC5-5-N-N).

The main switch turns on the power for the CNC, the spindle, light and the controller.

This will power on the CNC mill only, not the spindle. The spindle is typically not plugged in for safety reasons, plug in the spindle only as late as possible and not while you prepare the machine for your job.

Homing the machine

This CNC has no auto-home. Always run the homing operation as first step directly after startup!

Start by homing the machine. If the text „Reset“ blinks red on the screen, press the reset button (1). Press the “Origin Operation“ button (2). In the menu, select „Return To Home“ (3).

Navigation basics

On the panel, use the XYZ +/- buttons to move the spindle. Always home the spindle at the beginning of your session. If properly homed, softstop settings should prevent the spindle from crashing into the sides of the machine, but navigate with caution.

When using the jogwheel, press the button on the left side and then move the wheel. The X1, X10, X100 switch controls how far the spindle moves per click of the wheel. If set to X1, one click is 1/100mm. X10 is 1/10th and at X100 one click moves 1mm. Be extra careful when you move in z-direction not to break your router bit.

Setting workpiece origin

Coordinate system of the CNC mill:

Note that the machine zero point is in the top left front corner of the machine and the spindle moves down into the negative Z direction.

Set tool height / z-coordinate:

Carefully move down the tooltip onto the reference plane of your workpiece (usually the surface). Wiggle a piece of paper in between the tooltip and the workpiece and move the head down in 0.1mm or smaller increments until you start to feel the resistance and scratching.

Zero z-coordinate:

Press the „Coordinate Operation" button (1). Press „Z Axis Zero" (2) to set zero of the work coordinate for Z in the current position.

Set x/y-coordinate:

Move the tooltip to the X and Y position that you have set up as your origin in the CAM software.

Zero x/y-coordinate:

Zero the work coordinates for X and Y by pressing „X Axis Zero" and „Y Axis Zero" (1,2). You have now fully set-up the zero point of the work coordinates to be in line with the origin of your workpiece in CAM.

Load CAM/gcode file

To load your program, insert a USB drive with your gcode file. In the control-panel, select "File-Open" and navigate to your USB drive and the *.tap/nc/gcode file and select "Open". The file extension doesn't matter, Fusion uses tap, FreeCAD nc or gcode, at the end it is a gcode file which is readable in a text editor.

Last Checks

Before the last steps, now do a last check not to ruin anything. Make sure the Machine Zero is set-correctly and compare it one more time to your fusion settings. Move the spindle to clearance, in other words make sure it is not touching any material.

Are you sure, that the height is correct and you are not cutting into the work table? Are you really sure? Good.

Dust Protection

Dust & chip protection: If you are milling metal, position the U-shaped protection box over the work table. If it is wood, also hook up the dust shoe and a vacuum cleaner! Don't use the vacuum cleaner if you are milling metal. Metal can get very hot and set the vacuum cleaner on fire.

Start the Spindle

Now it is time to plug in the spindle, press the start button and adjust your spindle speed. Be aware that adjusting the spindle speed takes time, turn the button rather careful and give the machine time to reach its speed.

Start the job

RUN > Restart starts the program

Stop and Emergency Stop: In case of any issues don't hesitate to hit the big emergency stop (cuts all electricity to spindle and stepper motors) or for smaller issues the stop on the jog-wheel (stops the program, moves to home after reset).

After finished, shut down the spindle and wait until it came to a full stop. Be careful: Endmill will be very hot!