Mr Beam Shield - Instructions. #01 laser driver #02 power source #03 axes & motors #04 miscellaneous #05 safety #06 usage & appendix

Transcription

1 Mr Beam Shield - Instructions #01 laser driver #02 power source #03 axes & motors #04 miscellaneous #05 safety #06 usage & appendix front back

2 What is it? The Mr Beam Shield was developed within the Kickstarter project "Mr Beam - a Portable Laser Cutter and Engraver Kit" (see Beeing compatible to the grbl firmware ( bengler.no/grbl), it combines a laser diode driver with up to 3 stepper motor drivers on an Arduino Uno shield. We recommend the usage of our Mr Beam grbl fork which is already configured to the shields features. You can find it at mrbeam. What can I build with it? Originally the shield was designed for the Mr Beam laser cutter kit, but it can be used for every laser device which uses stepper motors in the mechanics. Besides laser cutters this can be laser sintering 3D printers, 3D scanners, laser projectors or other robots. Thank you & Have fun! By purchasing this shield you have supported a piece of open hardware - thank you! We enjoyed the development of it and will continue improving it. We hope you find our work useful and it will help you to be creative. Whatever you do, take care about yourself and others. We would love to see your work in the social networks. Tag it with #mrbeam to catch our attention. Have fun! Send any feedback to info@mr-beam.org. #about

3 Laser diode driver The Mr Beam Shield features a dimmable and efficient laser diode driver with a maximum output of 1500mA. The output current has to be set before connecting a laser diode. Check the data sheet of your diode for the maximum current and place the jumper according to the following table on the right Setting the current too high may destroy your laser diode. Before connecting the laser diode check twice the polarity of your diode, the cable and the connectors in between. A false polarity will destroy your diode. Interlock connectors The shield provides 2 connectors for interlock switches or sensors. Both have to be closed for operating the laser. Laser Diode - + 2x Interlock Current Selector CS1 CS2 CS3 Cooling Fan - + Laser intensity +5v ground pwm signal Cooling Fan Connect a cooling fan at this two pins. The voltage supplied at the + pin equals the input voltage from your power supply. The fan can be switched with the commands M08 (on) and M09 (off). CS1 CS2 CS3 Max Output Current 350mA 700mA 1200mA 1500mA #01 laser driver

4 Power in The shield supports a wide input voltage between 12V and 24V. When using your own power source please check that the power jack has the correct polarity. Reset, Cancel, Hold, Resume Buttons For easy wiring the shield has a dedicated connector for each control button supported by the GRBL firmware. Just plug in the button's cables - that's it. Arduino Power This little feature powers the Arduino under the shield with the supply voltage from the power supply connected to the shield. A voltage converter provides 5V output to the Arduino with a maximum of 1.5A. It is even enough to power an attached Raspberry via USB as well. To enable this feature, place a jumper on the two pins. Power in + - Reset Cancel Hold Resume Arduino Power #02 power & control

5 Motor axes: The Mr Beam Shield can control up to 3 independent axes. It has 3 sockets compatible with Pololu/ Stepstick stepper drivers like the ones used on many 3D-printers. While the Z axis has only a single stepper motor, the other axes have double motor connectors. This allows to drive two steppers with a single driver and is useful for a double motor axis like the Y-axis on a Mr Beam Senior. The connectors are using the reprap-style pin order (1b, 1a, 2a, 2b). Turning the connector 180 inverts the motor direction. Check the orientation of a stepper driver before plugging it in. The "enable" pin of the driver is marked on the shield as well. Z-Axis Z1 Z2 Y1 Y2 X1 X2 Endstops Y-Axis X-Axis The 3 jumpers marked with MS1, MS2, MS3 configure the micro stepping mode of the driver. Depending on the driver's chipset the modes may differ. This table shows the settings for the common A4988 chip: MS1 MS2 MS3 Microstep Resolution Micro stepping Full step Half step Quarter step Eighth step Sixteenth step 2x Motor 1b 1a 2a 2b Driver socket Enable pin Endstops: The shield provides 2 endstop connectors for each axis. Micro switches can be attached directly, #03 axes & motors

6 A5 Mode The assignment of the Arduino pin A5 is configurable. It can be used to switch the power of the AUX connector or as an additional sensor input. Place a jumper to enable the AUX power out, leave it open for using the sensor 2. AUX This two pins are an additional switchable power outlet. It switches directly the input power and can handle a maximum of 1A. When using it ensure that the A5 mode jumper is closed. Serial The serial rx/tx pins from the Arduino have its own connector here. The RX/TX pins have 3.3v logic levels, but it is no problem to use them with 5v as well if the counterpart is flexible as well. Additionally there are both voltage levels and ground available as well. Sensor Input Though the analog Arduino pins A4 and A5 are not used in standard GRBL firmware, the shield is ready for future developments and provides own connectors for them. In combination with a +5v and ground pin for each, it is easy to plug in common sensors. When using the sensor 2 ensure that the A5 mode jumper is open. TEC Signal Another thing for future development. Currently not supported. #04 miscellaneous AUX - + Serial ground +5v +3.3v rx tx A5 Mode TEC Signal +5v ground signal Sensor Input Sensor 1 Sensor 2 sense +5v ground

7 Laser Classification IEC classiefies laser products into different categories depending on light emitted, wavelength and eye safety. Classes for typical laser diodes are given below. Class 2, 2M / US Class IIa, II Caution, normally visible laser light less than 1.0mW. Considered eye safe, normal exposure to this type of beam will not cause permanent damage to the retina LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT Max Power: 1000mW Wavelength: nm Classified according IEC LASER RADIATION LASER APERTURE DANGER LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION DIODE LASER 1000mW MAX at 445 nm CLASS IV LASER PRODUCT Class 3R / US Class IIIa Danger, visible laser light between 1.0mW and 5.0mW. Considered eye safe with caution. Focusing of this light into the eye could cause some damage. Class 3B / US Class IIIb Danger, infrared (IR) and high power visible lasers < 500mW. Considered dangerous to the retina if directly esposed. Class 4 / US Class IV Danger, laser output power greater than 500mW. Class 4 lasers are capable of causing injury to both the eye and skin and will also present a fire hazard if sufficiently high output powers are used. You are responsible for the correct classification of your device. Additionally you have to put all safety labels on it according to your local regulations. Some examples of such labels are shown on the right. Check your local regulations for chosing the right ones. Safety Glasses Laser light is very intense. The natural winking reflex is not able to protect your eye. Always protect your eyes with appropriate safety glasses when operating a laser. Appropriate laser safety glasses need to block the laser's wavelength sufficiently. Sunglasses or just dark glasses are not able to do that. In addition to safety glasses you should consider to build a safety housing around your laser device. Be Responsible Always take care about yourself and others. Operate lasers with maximum attention at any time. Respect Local Laws and Regulations Almost every country has its own laws and regulations for operating a laser. You are fully responsible to respect and act in compliance with these. #05 safety

8 Usage The shield was designed to be used with the popular grbl firmware. We recommend our own fork at which is preconfigured to the shield's pin layout and features. Flashing GRBL Checkout Arduino for detailed multiplatform instructions how to flash the firmware on your Arduino. Use the precompiled grbl.hex from G-Code In addition to the standard G-code supported by grbl (see the Mr Beam version has reused some commands for controlling the laser intensity. Replace # with appropriate parameter values in the examples below. Laser Control M03 S### : switch laser to intensity. Intensity is number between 0 and 255. If the laser was switched off before it will be switched on. M05 : switch laser off. Fan Control M08 : switch cooling fan on. M09: switch cooling fan off. Movement $H : do a homing cycle G21 : switch to mm units G90 : switch to absolute coordinates G92 X0 Y0 Z0 : set coordinate origin G0 X# Y# : rapid positioning move G1 X# Y# : move to given position with the current feedrate F### : set feedrate Additional Information Resources The internet is full of information about laser technology and safety. Some (but not all) information resources are listed below: Safe usage of lasers Safety glasses and many more. Laser cutting GRBL / G-Code Accessories #06 usage & appendix