CNC foam cutting machine. Management / Habr
Spring is coming soon and many people will want to decorate their home with foam decor. And someone plans to insulate their home, waiting for this winter. I can’t help here, there won’t be a cheap way here, but I’ll tell you about foam cutting for those who already have a CNC machine. I will describe a few main points for those who do not succeed.
How to choose foam for shape cutting.
Usually, dense foam is used for decorative elements. M35 (Density 35). It takes longer to cut, the cutting speed is slower. but it is dense, although the main rigidity is provided by the coating, the foam base must also be rigid.
M25 – This foam is used for insulation panels such as “TERMOPANELS” and “POLIFASAD” for decoration, if you want to save money.
density M15 not used for shaped cutting. Only as packaging.
Extrusion polystyrenesuch brands as “Pinoplex” “Polpan” “TechnoNikol” roughly correspond to the density M45. At first, they were invented to be placed under the screed on the floor, but then they began to be glued to the walls. but the dense foam does not provide more thermal insulation, so it is up to you to glue or not on the walls.
How to choose a CNC machine
When cutting foam plastic, there is nowhere to escape from the laws of physics, foam plastic melts at the same speed and at the same temperature on all machines. It melts as 98% of all CNC machines cut it with a heated string, and it melts the foam.
Debris and moisture in the foamThe main difficulties in cutting arise precisely from the moisture inside the foam “Loaf”. Moisture cools the string inside the marriage in details from this.
Garbage in the form of twigs, pieces of other foam are added during production. and moisture is a consequence of poor drying. Moreover, there is moisture inside somewhere, and somewhere not.
CNC foam cutting machine is a complex
The frame of the machine and the software for it work together. If the software is not convenient, it will take a lot of time to set up and prepare the file for cutting.
Below is a professional program for cutting foam in 2D. since the machine operator often sees the computer only at work, it is very important that he immediately orients himself and starts working.
Below I will give an example of the well-known Match3 program so that it is visually clear what a friendly interface means.
Let’s go back to the foam, the foam manufacturer can save on raw materials, because this is what makes his profit. The less raw materials were placed during production, the less dense the foam.
But less dense foam cuts faster, so less dense doesn’t mean bad.
For example, one “Loaf of 35th” will be cut for 3 hours and “Loaf of 25th” of the same parts and the same dimensions will be cut for 1.5 hours. thus, in one case, the operator will cut 2 loaves per shift, and in the other, 4.
Water takes time to evaporate. And at the moment of cutting, the heated “string” finds moisture inside the block of foam and begins to cool down sharply, as a result, it ceases to have time to melt the foam, and it is necessary to reduce the speed at which the machine moves. Machines with electronic heating have few options “on the go” to change the speed and heating, while manual machines do not have such an option.
Therefore, as soon as the machine operator heard the hissing of water, or saw that the corners of the parts are not sharp, but “Oval”, he should reduce the speed by several conventional units. In this way, the machine will start to move more slowly and have time to melt the foam. But here the second nuance of “burn” is included, this is the empty distance in the foam left by the heated “string”. We usually use nichrome wire thickened 0.4 mm as it is cheap and can be stretched well. The 0.4 mm wire should leave a burn or cut thickness of approximately 2-2.5 mm. If you do not reset the heating temperature, but only the speed, the scorch will increase to 4-4.5 mm, which is already a lot. The detail will be “clumsy”, small details and grooves will lose their expressiveness.
So it turns out that you need to reset the speed and slightly reduce the temperature when “Ovalite” corners.
It is not recommended to raise the temperature! Since the water vapor in the foam block is not homogeneous, quality parts will not be produced. There will be many marriages.
The next rule is that foam must be cut from top to bottom.
Since the “burn” evaporates 2.5 mm of foam from the top of the part and 2.5 mm from the bottom, the block will fall apart with each row of cut parts. Already after 5 rows, the block will sit by approximately 25 mm. And if we cut platbands for windows with a thickness of 40 mm (thickness of the block is 600 mm, in my region), then there will be 13 rows.
Machine tools and their construction
As I wrote at the beginning, there is no difference what the design of the machine is.
Machine tools on cables.
This type of construction got its name after the drive.
Stepper motors wind special cable pulleys. Thus, it turns out that one closed cable in a ring moves the Y axis, and the same cable and motor move the X axis. The use of the cable not only makes the entire structure cheaper, but also ensures synchronicity of movement. Since the cable is practically not stretched, the movement of the carriage on one side of the machine also shifts the carriage on the opposite side. Discrepancy is possible only if there is mechanical backlash.
Machine tools on belts.
Such machines have two independent portals and the movement of carriages is carried out with the help of belts. A toothed belt is used.
Since the motors are not connected mechanically, that is, there is a possibility that the movements will not be synchronous. This feature is a feature. This feature will not be useful for cutting decorative products.
And the asynchronous principle also works correctly, only if it is possible to configure and manage both portals independently in a software way. If the program does not include the versatile management function, it is incorrect.
Machine tools on the ShVP.
The SHP gives excessive precision of movement, but at the same time, other mechanical solutions must also match.
ShVP is suitable for moving heavy carriages with several cutting strings. The design of the machine is the most expensive.
Exactlyyou machine is how tightly it is assembled. Accuracy is often called repeatability. That is, repeatability is the extent to which two details will differ, given that other conditions are the same.
For facade decoration, namely, machines for shaped foam cutting are used for it, it is not so important how the final product corresponds to the line and corresponds to mm and cm. It is much more important how all the details are the same. If, out of thirty identical parts, you see that the dimensions differ by more than one millimeter. This means that the repeatability is low, you need to pay attention to the mechanical part of the machine.
1. Perhaps the cutting string is not taut, the wire expands when heated and the springs that previously held it under tension begin to sag. Either you need to change the springs or pull the string tighter.
2. Perhaps the pulleys on the motors have loosened and when the motor turns, they do not turn with it. It is necessary to tighten the bolts on the pulleys.
3. Maybe the cable or belt is not taut. It is necessary to check the tension and if it is not there, then tighten it.
4. Perhaps the bolts on the frame have loosened. All bolts should be checked and tightened. Pay particular attention to the bolts that hold the cable to the frame or the bolts that hold the belt to the frame.
On the example of ***** of this program, we will explain the main functions of the machine, which are used when cutting decorative elements.
On the right side of the screen we see:
1. speed control menu
2. The number of copies of the open file. Number of rows and columns.
3. Temperature control.
4. On/Off button. heating the string
5. On/Off motor power button
6. Start button and manual control arrows
7. Open file button
8. Button to change the direction of file playback
9. Button to display the object vertically
10. The button to display the object horizontally
11. The button to tilt the object by 90 degrees
On the screen we see an open file, it is a series of 12 elements arranged with a spread.
The automatic cutting cycle consists of:
1. Opened the file
2. Set the speed at which the machine will move and the temperature of the string
3. Press the button to turn on the heating of the string, Press the button to turn on the motor power
4. Press the Start button
During the cutting process, you can change the cutting speed and heating temperature.
1. When pressing two arrows on the keyboard at once, the machine starts to move endlessly in the direction where we pressed the first arrow. At the same time, with a given speed and temperature. If the heat button is not turned on, the machine will move at maximum speed. You can stop the machine by holding any of the arrows for 2 seconds. After releasing the arrow, the machine will stop.
2. When holding down Ctrl and pressing the start button (short or long), the machine will move according to the program in the reverse direction.
3. With the motors turned off and the string heating, holding down the start button will show on the screen the path along which the machine will move.
Dimensions of parts
Dimensioning and drawing are done in graphic programs such as CorelDraw or AutoCAD
These powerful graphic editors offer a wide range of possibilities for drawing.
Size change, partial change, when only part of the points that make up the object change. Graphical editors are a very big and big topic, which is not covered in this article.
Editor for 3D cutting
This editor is needed to create cutting files on a rotary table.
The detail is created from a profile drawn in the 2D editor and repeated several times. Sometimes the function of simultaneous cutting along two axes X and Y is used, and at the same time the rotary table rotates. This gives additional interesting forms.
I will describe the steps on how to create files
1. After opening the program, in the upper left corner, click the “File” button, then “New” in the window that appears, select the desired part profile in PLT format
2. After the profile has been selected, this profile will appear on the screen, further up. click the “Settings” button, then “Increment angle”
Enter the increment value in degrees. For example, 10 or 36 or 90 degrees. Usually this will be the number in the sum of all the repetitions, which gives 360 degrees.
3. After that, press the “Face Copy” button as many faces as you plan to get. Let’s say the Increment is set to 36 degrees. So, by pressing the button 9 times, we will get a full revolution of the rotary table.
4. Next, click “Designer” “Change the direction of faces” and enter the number 1, press Enter.
5. Now we can save this file in PL3 format, then open the machine tool control program and start cutting.
In this guide, I tried to describe in as much detail as possible the order of all actions for a quick start. This manual is recommended to be shown to novice operators so as not to repeat the same thing several times. I also tried to show several construction options, their pros and cons.
Author – Alexey Bykovskiy
Maybe you cut the foam differently, write and I will add to the guide.