Welcome to Tea with DidiFeb 28, 2020
The CO2 laser tube is cooled by running or pumping water through the pipe.
This is necessary to extend the life of the tube, or it will overheat and power off quickly and will not run in the end.
CO2 lasers have expensive chillers.
Commercial chillers may be more expensive than low-cost laser cutting machines.
This project provides directions on how to make low cost chillers for CO2 laser cutting machines, whether you are a cheap \”K40\” laser or a beautiful Commercial Full Spectrum Laser.
It will show the construction of the complete chiller system, including an Arduino thermostat enclosed in the acrylic custom laser cutting project box.
The video below shows the action of the thermostat when water cools below 56 degrees Fahrenheit.
Please see my previous article on building a CO2 laser water flow rate monitor and alert.
The chiller system consists of three main parts: the parts list below covers all of these parts and provides low
Source of cost available.
Note, however, that I have used parts that are easily accessible in my small number of parts where possible.
I also used Amazon Prime to save shipping costs if possible, or I found parts available locally.
Fortunately, in San Antonio, Texas, we are fortunate to have the following stores offering the many items needed 🙁
Note this is not a paid endorsement-
Find similar local shops and support them in your area! )
It\’s also worth noting that when Shack closed many of their stores in San Antonio and component parts, most of my electronic inventory came (e. g.
Switches, wires, Arduino shields, etc. )
You can get a big discount.
Fortunately, even if they didn\’t really take over the manufacturer market, we still have some Radio Shack stores left.
The list of parts below is the system I will record in this article.
However, you should know that I did several attempts before working out this design.
In some photos, you may see the parts you have tried before.
In particular, my first design used a homemade water cooling block and a separate Peltier cooler.
It works, but it\’s not as good as the system I\’m going to introduce.
Component List chillers work by slowly pumping water from a 5 gallon insulated \”beverage cooler\” into a set of \”water cooling blocks\” designed for CPU cooling.
The two blocks are connected with vinyl pipes to increase the time for water to contact the cooling surface of the block.
The water is pumped into one of the blocks from the drink cooler, then pump into the other, and then pump into the drink cooler.
Each water-cooled block is connected to the cold side of peltier (a. k. a. thermoelectric)cooler.
The hot side of the cooler is connected to the CPU cooler with the fan–
One per peltier cooler.
By removing heat from the thermal side of peltier, the cold side is able to freeze the water in seconds.
Therefore, the pump must remain in operation when supplying power to the cooler.
Also, if there is no CPU cooler to take away heat from the thermoelectric cooler, the cooling side will not remain cool.
Please note that the hot side becomes hot enough to cause serious burns.
Do not power it on before connecting to the radiator of the CPU cooler.
Our 92 GPH pump allows as slow pumping speed (
Flow adjustment function).
This increases the time for water to be cooled before being pushed back into the container.
The thermostat is responsible for turning on the pump, thermoelectric cooler and CPU cooler fan.
It also turns on the chassis fan when others are running.
The diagram above illustrates how these parts are stacked and connected together.
The CPU fan 12 volt line and the 12 volt line of the thermoelectric cooler are connected together, but each group remains independent. Use thicker (lower gauge)
Wires for thermoelectric coolers and ground wires.
Each cooler is 90 to 92 watts, so a lot of current is consumed.
I\’m using 22 ad hoc working groups of stranded lines.
It works, but it becomes very warm.
I suggest you use a thicker wire.
Common ground wire can be used.
Radiator compounds are used on each side of the thermoelectric cooler, on each side of the water-cooled block, and on the bottom of the CPU cooler radiator.
As shown in the next step, the CPU cooler will be bolted together to fix everything in place.
They need to be bolted through some kind of material used as a frame.
Once the bolts are connected together, the wires all extend to the wires connected to the thermostat, and after testing everything is OK, some spray
Foam is used for heat insulation around water-cooled blocks.
To improve efficiency, you can add as much insulation as possible.
The following figure shows the complete chiller installed on the 5 gallon beverage cooler.
To assemble the chiller, start with the following sections: prepare for the CPU cooler. The CPU cooler is equipped with legs attached to the plastic holder.
Remove the plastic holder so you only have the metal legs.
There are also screws in the package to connect the legs to the radiator.
Each leg is marked with L or R for proper positioning.
Connect the legs.
The photo below shows the legs at the time of shipment, the brackets on the left and right are removed, how they should be attached to the radiator.
Prepare the installation block. . .
Use a piece of transparent plastic like a bakery container (shown below)
To mark the location of the hole drilled in the mounting block.
Then drill again.
After drilling, cut out the center fit around the thermoelectric cooler and water-cooled block.
One side must be cut (
You can try drilling.
Allow the tube to reach the water cooling block.
I cut with a band saw, but with patience I can use a hacksaw or even a clamp saw or a roller saw.
In the photo to the right below, you will see the bracket/frame I used for the final product.
A piece in the upper left corner is used together with the drill hole to tie that far corner.
Remove the label from the water-cooled block.
A little walk will help.
Assemble the cooler stack with the ready frame and the label removed from the cooling block, and assemble the cooler stack as shown in the chart in the previous step.
To do this, reverse a CPU cooler and apply the radiator compound to the radiator.
Then place the first peltier/thermoelectric cooler Heat side on the radiator.
After that, apply the radiator compound to the top–
Cold side of thermoelectric cooler.
Note: If you do not know which side of the Heat side of your peltier cooler is, please check the specifications it comes with, or when holding the cooler between your fingers, apply the 9 volt battery briefly to the wire with proper polarity.
It\’s just short, or you will get burned.
You will soon find out which side of the heat is.
Next, apply the radiator compounds on both sides of each water-cooled block and stack them together.
Arrange the stack the way you like, but I chose the entrance/exit facing the adjacent side.
I started with the vinyl tube as well, but it does make more difficult.
You will notice in the photo below that in one of the tubes I inserted a short section of 1/4 \”O. D.
Copper tubes that help slow the flow slightly.
Once the two water-cooled blocks are stacked together, there are radiator compounds between each layer and at the top, place the second thermoelectric cooler on the top of the stack, under the cold side, up the hot side, and add radiator compounds to its top.
Now put the final CPU cooler at the top of the stack and use enough bolts and nuts to go through the holes on the legs of the CPU cooler at the bottom, through the mounting block holes, and then through the top CPU cooler legs.
Tighten this up but not too tight-
Don\’t crack your peltier cooler!
Fill the foam with some gaps (
Wal-Mart and hardware stores)
To fill the gaps around the water-cooled block.
It is very slow to do so, or it will get out of control.
To protect your table, be sure to put something under the table.
I used some Saran packaging.
Also make sure the wires are not surrounded by foam.
They should go through it, but not buried in it.
To complete the chiller, weld all the black wires to one line of ground.
The wires should be 18 to 24 inch long.
Be sure to use the heat shrink tube to insulate any bare wires.
Connect the ground wire to your 3-pin 1-
Plug pin connector.
Then weld the two red wires of the CPU cooler fan to one wire and attach it to the 3-pin 2-pin
Plug pin connector.
The wires should be 18 to 24 inch long.
Ensure that any bare wires are insulated with a heat shrink tube.
Finally, weld the two red lines on the thermoelectric cooler to a single line between 18 and 24 inch long and weld the other end to 3 pinspin connector.
Similarly, insulated any bare wire with a heat shrink tube. The red wires (pins 2 and 3)
Will be connected to an independent relay in the thermostat.
The other side (
The relay will be connected to the 12 V output of the power supply. The black (ground)
The Wire will be connected directly to the power-supply ground.
The installation cooler is done, but you need to find a way to install it on your 5 gallon drink cooler.
This is at least an option.
Maybe you will have the idea of a better way to wrap the cooler.
It needs to be within the range of the thermostat and the tube connected to the water pump inside the beverage cooler.
The photo below shows how I can use 3/16 acrylic and a set of bolts to make a stand that will slide into the cup holder slot on the drink cooler.
The final product unit thermostat unit consists of the following components: Power supply Please note that the 12 V power supply will supply power to all of the following components: I recommend using a power supply capable of 30 a @ 12 V.
Most of the electricity consumed will come from two 92-watt thermoelectric coolers.
First of the build up of Arduino UNO connecting ArduinoThe Seeed Studio relay shield.
In addition to this, we will place a custom shield made of a prototype PCB shielded with ayp82.
Arduino pins are connected as follows: pin 2: push up instantly-
The button switch is connected to the ground on the other side.
Pin 3: push instantly down-
The button switch is connected to the ground on the other side. PINS 4 –
6: Seeed Studio relay ShieldPIN 10 use: connect to the signal line (Yellow or white)
Waterproof digital thermometer.
Be sure to connect it to a pin on the stereo plug.
I chose the pin that was connected to the most extended part of the plug.
When you weld the ip65thermometer line on the stereo jack, make sure it matches.
You also need to run a 4.
7 k ohm resistor from Pin 10 to 5 v line.
Pin A4: SDA connection on the serial LCD backpack board.
Pin A5: the SCL connection to the serial LCD backpack board.
Complete schematic note: the schematic is made using EasyEDA, a free web-based schematic capture program.
I recommend supporting their business so that the service remains free of charge.
Connect the rest. . .
As can be seen from the schematic diagram, the circuit is built on the top of the Arduino shield and connected to the lower layered shield-
Seeed Studio relay shield.
In order to maintain all the modularity, external components–
Chiller and thermometer probe connected via plug
Be able to connect, but it\’s up to you to do this specifically.
You will see from the photo how I did this and it worked well.
In the schematic diagram, the relay is displayed using the label of the relay on the relay shield.
Normally connected in all 4 cases (N. C. )
The Pin is not connected to anything.
It\’s not very important which relay controls which items, but it\’s better to separate them, which will allow you to customize the sketch to change the time to suit your needs.
A small part of the circuit uses AC power.
Of course, the 12 V power supply is powered by an AC power supply.
In addition, the chiller pump is powered by an AC power supply, and the relay controls the power supply of the pump, so it will only operate when the chiller is turned on.
Planning and preparing the project box will make things easier when building blocks and connecting components.
This part of the project is something you should tailor to the material at hand and your own taste.
If you like the project box I built and you can use the LaserCAD file, or.
The platelet file attached to this step, you can match my box in each detail or change the content as needed.
If you use a switch or connector of different sizes, or even if your power cord size is different, you can change the cut-out as needed!
Design box my project box is made of 3/16 \”acrylic.
The box pattern is made using BoxMaker (
BoxMaker will allow you to input the size and thickness of the box and then generate a PDF file containing each panel.
My laser cutter is controlled by LaserCAD and LaserCAD cannot import PDF files, so it is necessary to import PDF files into Inkscape first and then save each panel as a DXF file.
You can import the DXF file into LaserCAD, and then add cuts to external components such as LCD, switch, and chassis fan in LaserCAD.
Use my file if you use the attachment.
The pwj5 file with a laser cutter that supports LaserCAD simply takes note of which colors are enabled and the cutting settings, and adjusts as needed.
Since I made this box in several channels, the current cut setting only reflects the last channel.
There is a file for each panel and a file for making Arduino shelves.
It is also very important to note that some lines marked as cutting lines are not for cutting, but for aligning screw holes, etc.
The Pwj5 files are not selected for these files, or the laser power level of that color is set too low to be cut, usually both.
There is also a group.
Platelet file for each panel.
These are exported from LaserCAD.
You can use.
Open and edit the lt file of the drawing in AutoCAD, or you can use the free online converter to convert the lt file to PDF or other formats used with the laser cutting software.
Feel free to modify the file as you need it, including removing my name and putting your name there!
Arduino shelves have passed-
Holes that match the holes in Arduino Uno, making use of 4-
40 bolts and nuts each.
Assemble each panel cut and appropriate cut into the box and you can now insert the unit and solder wire as needed.
Glue the box with external parts attached to the box panel and wires attached to the shield (see next step)
You can start sticking the box together.
First fix the Arduino shelf on the back panel.
To protect your desktop, be sure to put wax paper or something like that underneath.
In the case that the Arduino shelf is in place, you may want to connect the Arduino and then cement the back plate to the bottom plate.
Cement each remaining panel in place when most convenient, but please note that you prefer to do it in the following order best: by soldering the header pin to the shield, welding the header pin is probably the easiest to start.
If you use a stackable head pin, you can place another Shield on this head pin if you need to expand your circuit.
I used what I had. the non-stackable pins.
In doing so, you may also want to attach a reset button, as you can see in my photo.
No need but I have one so I added it.
Soldering and connecting the LCD thermostat shield requires several wires to be connected from various panels.
If you don\’t mind the time and cost associated with placing a socket, plug or plug pin for the removable cable of the external unit, I highly recommend that you do so.
I didn\’t, largely because I didn\’t want to order them or wait for them to arrive.
Instead, I Weld (long)
With one exception, connect directly to the shield from the connector on the panel.
I happen to have a cable with a connector that fits perfectly with the LCD backpack.
I welded the end of the cable without directly connecting to the shielded connector (
A4, A5, 5 v and GND)
, Then plug the cable into the backpack.
Note: If you order and use the Arducam Series 16×2 LCD package I ordered from Amazon, you first need to weld the backpack to the LCD.
Follow their instructions. –
Or at least test, before welding, make sure that the ground on the backpack matches the ground on the LCD, as you can see in my photo.
The photo below shows 4 wires in the LCD series backpack connected to the shield on pin A4 (SDA)and A5 (SCL)
As well as grounding and 5 V wire connection.
The thermometer connection line is connected to pin 10, and the thermometer connection, the button switch, and the chassis fan power supply. A 4.
7 k ohm resistance is also run from Pin 10 to 5 V pads.
Instant push up
The button switch is connected to pin 2 and the other side is connected to the GND pad.
Similarly, the downward moment pushes
The button switch is connected to pin 3 and the other side is connected to the GND pad.
Pins 2 and 3 are used because they are associated with interrupts 0 and 1 for Arduino.
I also connected a wire from Vin to COM4 on the relay shield.
The NC4 on the relay shield enters the 12 v line of the 80mm chassis fan.
The ground wire of the chassis fan is connected to the GND pad.
This is because I thought of the case afterwards.
I found it quite warm in the box–
Mainly from the power supply.
By adding the chassis fan and powering it only when the cooler is running, the box stays cool.
The photo below shows all of these connections to the label. (
Click or click on it to enlarge it. )
Ardu supplies power to the power jack as shown below.
The red line will be connected to one of the 12 v terminals on the power supply.
The black wire will be connected to one of them-12v (ground)
Terminals on the power supply.
The Jack will be inserted into the Arduino.
Powering the CPU cooler fan, the thermoelectric cooler connects the wires of one of the 12 v terminals on the power supply through RelaysConnect to the NO1 terminals on the relay shield.
Connect another wire from another 12 v terminal on the power supply to the NO2 terminal on the relay shield.
Then connect the 12 v wire from the chiller Jack (3-
Pin audio connector)
COM1 on trunk shield.
Make sure this is connected to the 12 v wire of the CPU cooler fan on the other side of the cable.
This 12 volt terminal can be shared with Arduino power supply.
Connect 12 v wires from the chiller Jack (3-
Pin audio connector)
The red line of the thermoelectric cooler extends to the COM2 on the relay shield.
These relays will be turned on by the thermostat circuit (COM < -> NO)
When the water temperature is lower than the thermostat setting.
Note: I welded the Philmore male terminal (NO. 65-5021C)
For better connection, each wire that goes in and out of relays 1 and 2.
The AC power socket and the main power supply are connected by reconnecting the ground wire, and the neutral ac wire is connected to two power supplies (GND and N)
Direct AC socket with Chiller pump.
Exchange hotline (L)
Connect directly to the power supply (L)
Then arrive at the terminal COM3 on the relay shield.
From the terminal No 3 on the relay shield to the remaining L (hot)
Connection on the AC socket of the chiller pump.
The 80mm chassis fan power supply mentioned in the previous step, you can directly connect the 12 V voltage of one of the power terminals to the COM4, or you can run it from Vin on the shielded PCB like I did.
Again, you can connect the ground wire of the chassis fan directly-
The 12 v terminal on the power supply, or you can connect it to the ground pad on the shielded PCB.
Connect the 12 volt wire of the chassis fan to the NO4 terminal on the relay shield.
Put it all in. . .
Now that all the connections are done, you can connect the shield.
Now you can also put the remaining panel cement in place.
Remember not to cement the top panel!
If something goes wrong, you need to remove it to access the inside!
It will be comfortably installed without cement and the fan Shield will help to remove it.
A prerequisite library for attaching Arduino sketches.
In order to compile and use it, you need to install the following Library: I suggest building a small circuit and sketch to test each component before building a larger circuit, in case there is any change, you need a different library.
If you wish to use my sketch-
Yes, it is connected to this step as a thermostat. ino.
It should work with your Arduino Uno (or clone)
No change if you follow my route. How it works. . .
The thermostat is fairly simple, not unlike the one you use to control the temperature at home.
The LCD displays the current Fahrenheit temperature and degrees Celsius on the first line and the current settings on the second line.
Open the pump and cooler when the water temperature is higher than the set value.
When the temperature drops 1.
Set 75 f ° below and the cooler, pump and fan will all turn off until the temperature is higher than set again.
Input lock because it is difficult to get a clean signal from the Arduino interrupt pin (
Maybe this is my old question.
Used Arduino Uno?
Or maybe because of noise from other parts of the circuit)
, I added the \”set Lock\” feature.
In order to change the thermostat settings, you have to hold down the up and down button for 1 second.
When this is detected, the LCD will display the message \”—-UNLOCKED—-
\”Enter Temp on the top line, on the second line:\” For 3/4 seconds.
When unlocking, the up and down buttons can be used to increase or decrease the thermostat settings.
If the button is not pressed within 10 seconds, the input lock is restored.
The lock will also be restored if both buttons are pressed and held for 1 second at the same time, but note that if no rebound causes the temperature setting to increase or decrease by one or two, it can be difficult to press both buttons at the same time.
For this reason, you may prefer to have the system re-
10 seconds from line lock by holding the button still.
Read the temperature please read the sketch for all the details of how the code works.
Here, I only emphasize part of it.
In particular, the TemperatureModule class takes advantage of the OneWire 2 Library to read the temperature from the B20 in a digital waterproof temperature probe that meets the protection level.
In the code of the TemperatureModule, the example sketch of OneWire month.
It provides only two methods: Initialization ()
And reading temperature f (). Initialize()
Must be called before the first call to ReadTemperatureF.
ReadTemperatureF will return the temperature in degrees Fahrenheit and will fill a passed variable in degrees Celsius.
After the class is defined, the instance of the TemperatureModule is declared on line 171 of the sketch: You will also notice the g-LCD on line 172
Example of LiquidCrystal_I2C.
Both global objects use macros defined at the top of the file.
These macros also define each Arduino pin used by the sketch: SetupLines 1 to 3 including the library used by the sketch.
In the third line, you will see the inclusion of the EEPROM. h.
This will be used during the setup and after the thermostat settings are adjusted to keep the temperature in the Arduino\’s EEPROM in order to remember it when the power is reset.
The temperature is stored in one byte, allowing the temperature to be set from 35 degrees Fahrenheit to 85 degrees Fahrenheit.
It seems like a reasonable range for us to store simplified values by using a byte. The setup())
In addition to protecting the probe, this tiny modification will allow the thermometer to float underwater.
I\’m thinking of buying a 3/8 or 1/2 copper stick, drilling a hole large enough to insert the probe into it.
The bar will extend to the bottom of the drink cooler and pass the temperature to the probe.
In the end, I think it\’s good enough.
Now it\’s time to place the whole unit near the laser cutter and fill it with distilled water.
If your setting is where water can freeze, you should probably mix distilled water with antifreeze.
Put the lid on it and plug everything in and you should be able to cool the water now.
I tested in a room with an average room temperature of 75 degrees Fahrenheit, and in the case of non-continuous operation, the chiller is easy to maintain 54 degrees Fahrenheit.
While you may know this better than I do, I have read that 56 F is a good temperature to cool the CO2 laser tube. 11.
25 KWHI has already run the chiller
Stop 168 hours-
A whole week. The kill-a-
The reading of the electric energy meter is 11. 25 KWH.
These results are better than expected, although they may not be as good as one would expect.
My current electricity bill is £ 9.
3 cents per kilowatt hour.
Throughout the week, the room temperature averaged 75 degrees Fahrenheit and the laser was used only a few times.
If these variables hold up, my energy cost is about $0. 14/day, or $4. 41 / month.
It\’s about $53. 76 each year.
Your mileage may vary.
I am fortunate to live in a region where the cost per kWh is not as high as the national average.
I recently added a 8,000 watt photovoltaic solar system to my house (
To reduce energy costs–
$700 per month in summer! )
There is no doubt that this will also reduce the cost of running the device.
One thing I noticed is that when the pump of the laser tube is turned on, the water temperature always increases by 1 to 2 degrees, even if the laser is not used.
This is part of the expectation because the tube to the laser tube is not insulated and it is a considerable space —
The temperature moves compared to the path where water passes through the cooler.
But I\’m worried about 620 gallons. per-
The hourly pump I use to pump water through the laser tube is actually heating the water.
I will eventually try to use the outside (non-submersible)
A pump for this purpose, or a smaller submersible pump.
My speedometer shows that I only smoke about 0.
9 liters per minute through the tube.
Is it 54 liters or 14 liters?
26 gallons per hour
I upgraded to a larger pump and tried to increase the flow but could not exceed 0 at all.
9 liters per minute.
It is likely that some heat is caused by a pump that is trying to overcome a direct bottleneck.
While I am afraid of having to cut off and repair another pump AC power cord, I will comment in the future on the effect of using the smaller or outside pump mentioned in the previous step, the large pump I used to water the laser tube caused some warming of the water.
When I run for 30 minutes or more, it\’s clear that the temperature is going up much faster than I expected —
Up to 5 to 10 degrees.
I have now replaced that pump with an external pump.
The temperature still rises slightly when the pump is running–
Even if the laser is not used, it can be expected because the water flows out of the cooler and is cycled through quite a long pipe and laser pipe, none of which is insulated.
My test shows a temperature rise (Loss of efficiency)
The new pump is only 1 to 3 degrees.
It\’s worth exchanging.
As you can see from the photo, I switched to this small external pump I purchased via Amazon. com.
The pump can be 1. 2 GPH.
It\’s quiet enough not to be a problem.
As a 12 V Pump, I also have to add a 12 V power supply, which is what I have from ATX (computer)power supply.
Since this pump is external and needs water before powering on, I replaced the plug for the 5 gallon drink cooler and delivered the water directly from the cooler to the pump.
I also used \”I\” with a length of 1/4 \”. D.
The fuel line from the pump to the flow monitor helps with some insulation.
The flow monitor shows that the pump is able to move about 0.
80 liters per minute through tubing and laser tubes.
This is about 0.
10 liters per minute, less than my oversized submersible pump, but better than the pump that comes with the K40 laser.
Thermostat firmware update I also updated the thermostat firmware.
These changes are needed to solve the problem that the thermometer sometimes reads abnormally.
Now the average of the last 10 readings (Last 10 seconds)
Used to decide to turn the cooler on or off.
Also, any reading 5 degrees or more from the previous reading will be thrown away.
After 10 such conditions, the thermometer will be re-developedinitialized.
This seems necessary because 1-
Wired protocol for reading the thermometer.
The updated Arduino INO file (Thermostat. ino)
Attach to this step.
Although I almost gave up the system after I tried it twice, I was not very happy.
As mentioned, I will try to replace the main pump (
Pump to the laser tube)
To see if I can keep the water cooler during the laser operation, I will add a comment with the results on a future date.
As always, thank you for your comments.
Please also read my 1st articles on CO2 laser water flow speedometer and alarm.