K40 CO2 40W China Laser und Engraver
Engraving glasses and bottles
Focus via the motor table
What is a Rotary and what is it used for? A Rotary is used to laser or label round objects such as wine bottles, glasses or aluminium thermos flasks.
A laser can only perform 4 movements: right - left and back and forth. The X-axis is responsible for the right and left movements, the Y-axis for the back and forth movements.
With round bodies such as bottles or glasses, the laser would quickly lose focus due to its round shape. That's what the Rotary is for, it turns the glass a little in the Y direction after each lateral movement.
There are several Rotarys to copy and download portals. But none of them could convince me. So then I have to do it myself.
In the K40 China Laser, there is not much height left below the laser table. This should be used to the maximum. If the height is not sufficient, the bottom of the K40 can also be retrofitted with the plasma cutter.
The first version was already fully functional. In the meantime, I have further optimised the Rotary so that the last mm in width and height can be used. Now wine bottles up to 0.7l can be engraved without removing the bottom of the machine.
Building instruction Rotary for the K40
Somehow you came across this article. Probably because you have a K40 laser and would like to engrave round objects like bottles and glasses.
I was faced with the same project as you and was pretty much biting the bullet. No one really wants to help you and otherwise only at horrendous prices. That's why I decided to conduct a little experiment.
I took the time to develop a rotary and share it with you. I put together a list of components and laser files and wrote this report. I spent a lot of time on this and I think that this should be rewarded. If I could help you with these instructions you are welcome to send me a small amount via PayPal to contact@cigarbox-guitars. I will then see by the number of downloads if this is only used by people
if someone thanks me for something or appreciates something. Depending on that I will continue to put projects online or do without. Of course I would be very happy if you give my Facebook page https://www.facebook.com/cigarboxguitars.ch a thumbs up or even share it. Thank you and here we go.....
Parts list for Rotary
- Steppermotor 1.5A (17HS4401)
- 6 Kugellager 606ZZ 6 x 17 x 6mm
- 1 GT2 Riemen geschlossen 300mm
- 4 GT2 Timing Belt Pulley Aluminium 20 Zähne Bohrung 5mm
- 4 Gewindestange M5 je ca 300mm
- 2 Gewindestange M6 je ca 325mm (Antrieb)
- 2 Schrumpfschlauch passend zu M6 Gewindestange je ca 300mm
- 8 Gewindehülsen M5x20mm
- 4 Aluminium Rohr 7.5x1mm ~280mm
- Aluminium Winkel 40x15x1mm (Auflage auf Lasertsich)
- 3mm MDF
- 4 Innen 6-Kt- SchraubeM3x8mm mit U-Scheiben
- 8 Innen 6-Kt- Schraube M5x16mm
- 1 Innen 6-Kt- Schraube M5x30mm
First laser these components onto 3mm MDF
Always glue the two components together. Ideally, do this when you already have the ball bearings with you. This way you can apply the glue on one side and use the ball bearing to centre the components.
Note that one component has slightly larger holes. These are used to guide the threaded bushings. When the glue has hardened, the two lower holes must be countersunk a little on the outside so that the screws do not touch the laser table.
You are probably wondering why the motor mountings are also in the right-hand components? So that you can tension the belt without having to dismantle the whole Rotary. You only need to loosen the support bracket and then use the Allen key to loosen or tighten the screws through the holes. The slotted holes allow the motor to be pushed to the side so that the toothed belt can be tensioned.
Now you can cut the two support brackets to size and also countersink the two holes a little. Then assemble the Rotary. The threaded bushes are attached to the side parts with the Allen screws.
Does everything fit? You can now adapt the threaded rods and the lateral aluminium tubes to your table.
A larger recess is provided on the right-hand suspension and on the motor mounting. This makes it possible to insert larger bottles into the Rotary. The bottle neck then lies under the aluminium profiles of the truck table.
So I could optimise the last mm and even bottles with a length of 330mm fit into the Rotary.
Adapter for conical glasses
Of course, there are also champagne glasses that do not fly cleanly on the Rotary due to their conical shape. For this I have built an adapter. This can be moved on the Rotary. There are some slotted holes for ball bearings.
are provided. So it should also be possible to put conical glasses straight on.
What is a stepper motor?
The stepper motor is a stepper motor that moves by its step angle with each control. This step angle is indicated on the type plate, i.e. a 0.9° makes 400 steps and a 1.8° its 200 steps for one revolution.
The steps can then be specially controlled for whole-step operation, half-step operation, quarter-step operation or eighth-step operation,
Nema is a well-known cheap Chinese manufacturer and the number Nema17 that follows is only the size of the motor 42x42mm.
Where is the Rotary connected?
The rotary is driven by a stepper motor. This can be connected to the existing M2 Nano Board. For this purpose, the Y-axis (y-axis) that is not needed is unplugged and the retoary is connected to the socket that has become free. Attention: The stepper used should have a rated current < 2A. The Nano Board is not designed for higher currents and can otherwise be overloaded or even destroyed.
Help the Rotary turns continuously after switching on
No problem. In standard mode, the laser head always returns to its original position first. However, since we have exchanged the Y-axis for the rotary, the control expects the laser head to move to the end position in the Y-position and actuate the limit switch. So we have to trigger the limit switch manually. Some have a mechanical limit switch. My machine has an optical sensor. This is normally triggered by the metal construction. Take a piece of metal and hold it briefly between the two poles. The control system is already tricked and the Rotary moves into the start position.
Attention: Before you move the laser head, you must always press the "Unlock Rail" button in the K40 Whisperer. This will unlock the stepper motors. Otherwise you will damage the mechanics.
For calibration, it is best to draw a few squares and then send this file to the laser. I used a tin can for this and bordered it with masking tape.
Measure the caro after printing. Is everything correct? If the y-axis is not correct you can adjust it in the K40 Whisperer Settings. To do this, open the Settings > Rotary Setting tab or call it up directly with F4.
Select "Use Rotary Settings" and adjust the Rotary Scale factor if necessary. Then you can test the canister and the squares again and measure again.
Prepare graphic for the Rotary
How can we determine the maximum size of the bottle surface to be engraved? We'll have to resort to the mathematical bag of tricks. What was that again. Calculate the circumference of a cylinder?
2* π *r. r stands for radius or half the diameter. This can be measured exactly with a caliper. For example, a bottle with a diameter of 70mm has a radius of 35mm. This results in 2x3.14x35 = 219.8mm.
The maximum width of the bottle or glass to be engraved can be measured directly.
Now a new sheet can be created in the graphics program with user-defined dimensions.
I had already built a manual laser table for my K40 China laser. Meanwhile I would like to laser round parts like glasses and bottles. In order to use the maximum height of the laser, I decided to build a new table. This table should also have the possibility to hold a rotary. If it is not needed, it should be possible to dismantle it quickly and without tools so that it is not destroyed during normal use of the laser. The rotary should also be able to be focused with the motorised table.
Basic idea table from Thingverse with slightly modivised control system
What is needed:
- 3D Druckteile
- Arduino Nano
- Klemmbord für Arduino nano
- Stepper- Treiber
- Klemmbord für Stepper
- Kugellager 608 ZZ
- 5 Widerstände 10 K Ohm
- 1 Endchalter
- 4 Taster
- Litze und diverse Schrauben
- GT2 Zahnriemen
- GT2 Zahnriemenscheiben 8mm Borhrung
- GT2 Pulley
- Alu Profil 15x15mm
Height adjustable table with stepper motor
I bought a 3D printer to produce the necessary parts myself. The remaining parts such as trapezoidal spindles, ball bearings, toothed belt and stepper motor have been ordered. I still have a few days to print the plastic parts.
After printing the corner parts and motor mount, the table can be assembled with the aluminium profiles.
Built-in truck table. A piece of expanded metal is used as a cover to achieve the smallest possible reflection. Instead of expanded metal, a honeycomb table can of course also be used.
In the first step, an arduino nano is installed to take over the control functions of the table. 2 up and 2 down buttons are installed. I have found space for them on the side next to the temperature monitor.
The left buttons are responsible for the microstep function for the fine adjustment and the two on the right side for the fast up and down movement of the table.
I installed the control for the table in the laser's power supply. For the Arduino Nano and the stepper driver, I also used a board with terminals.
This way, the Arduino can be plugged into the designated pins and the connections do not have to be soldered directly to the electronic components. The stepper motor can be plugged directly into the driver.
Pull-up and pull-down resistance
What are the resistors in the diagram for?
So that electronic components receive a clear signal, so-called pull-up and pull-down resistors must be installed. In our control system, this is the case with the 4 manual switches and the limit switch.
When the contact is opened, the pull-down resistor pulls the voltage at the input down to GND, so there is clearly no signal on the input pin of the Arduino Nano. Without this resistor, the input pin does not receive a clear signal. With this circuit, the signal is clearly
Raspberry Pi Remote Desktop Connection K40 Laser
First, the required software must be installed on the Raspberry Pi. First, update the Raspery Pi to the latest version.
sudo apt-get update
sudo apt-get upgrade -y
Anschliessend mit dem Befehl
sudo apt-get install xrdp
install the required software. Now the Raspberry Pi is ready for remote desktop access.
To access the K40 Laser Cutter and Encraver modified with a Raspberry Pi4 from a laptop or desktop you need a remote desktop connection.
To connect, simply type Remote Desktop into the Windows search box.
Under Computer you enter the IP address of the Raspberry Pi. If you do not know this, log into your modem, e.g. 192.168.1.1. Under Network Connections you can find all devices with their IP address in the network.
Then press the "Connect" button. The following login screen should now appear.
Here you enter the username of your Raspberry Pi (normally = pi) and the corresponding password under Username. If everything is entered correctly, the desktop of your Raspberrty Pi appears on your laptop or desktop.
Share folders on the Raspberry Pi
In order to access the folder structure of the Raspberry Pi with the laptop or desktop, the Samba software must be installed on the Raspberry Pi.
For this you open the terminal and enter the command sudo apt-get install samba samba-common-bin
Now you have to set a user for samba with "sudo smbpasswd -a pi". This must also exist as a user on your Raspberry Pi. In the following example, we use the user "pi".
Then open the configuration file with sudo nano /etc/samba/smb.conf.
A folder share can look like this
comment = Laser-Share
Then save CTRL / O and confirm with Enter.
Finally, you only have to restart the service with "sudo /etc/init.d/samba restart".
Connect network drive
Now the folder on the Raspberry can be connected as a network drive on the desktop or laptop.
Open the Explorer. Right-click on the "This PC" icon.
Connect network drive
Select the desired drive letter
For the folder, enter the IP address or the name of the Raspberry PI followed by the folder name.
Now you will be asked for a password, enter the user and password of Samba (not the Raspberry password).
Now your Raspberry folder should be visible in the explorer.
Installing Fonts on the Raspberry Pi
sudo apt-get install ttf-msccorefonts-installer
I couldn't wait for my new speil stuff to finally arrive. But then I was completely surprised. I ordered it on Saturday and it arrived on Wednesday. It was only announced in about 1 1/2 weeks.
During my research on the Internet, I came across various articles. The China Laser is cheap, but it has a few deficits in the design. One of them is safety-related deficiencies. For example, a missing emergency stop switch. Or a defective earth connection. The cable lug of the earth conductor was clamped directly onto the paint. The other deficiencies are in the design. In this respect, we Western Europeans are still a nose ahead of the Asians. But this is also reflected in the price.