Simple but mighty DIY 4 axis CNC Foam Cutter - Theremino Controller (Not Arduino)! - RC Groups
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Dec 17, 2015, 12:36 PM
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Simple but mighty DIY 4 axis CNC Foam Cutter - Theremino Controller (Not Arduino)!


Hello everybody

this is the description of my first DIY 4 axis CNC machine.



It was originally described on our Italian RC forum in this Thrtead
I made it simple, cheap but with powerful open hardware/software controller - Theremino

I will write about Its open source electronics (Theremino Master Dil) and Open source GCode executor (ThereminoCNC)
I will write also about commercial software used to design a wing (GMFC - DevWing Foam) and a commercial Gcode Executor (DevCNC Foam).

Please consider this discussion as made by an absolute beginner, so you will shurely find errors or misunderstandings, be patient and comment if you like!!!
I will learn a lot from your observations, for sure!


The mechanic design was taken from many discussions on our forum like this thread (thanks to gregnapola and others), This one and many other web resources that I don't recall right now..

These are the mechanics for the 4 axis




They were made using 4 NEMA 17 (17hs4401n) stepper motors and drawer guides, plus some wood, some alu square tube, many iron pieces (plates and angular joiners) and 2 table legs.

Movement is operated by 8mm diameter 1.25mm/turn pitch screws.

On one side the screw is held by the motor trough a vibration dumping block
On the other side I used a support holding a skate wheel ball bearing





On the X axis I used a solution by Gregnapola to eliminate the dangling on change of direction.
It consist in two long nuts with a slightly compressed spring between them.



This way the carriage on X axis don't loose any motor step when changing direction and if you make some try with different spring compression you can achieve an almost frictionless movement of the screw trough the two nuts.
Last edited by pieri70; Jan 04, 2017 at 01:01 AM.
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Dec 17, 2015, 12:37 PM
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My control system is based on Theremino



http://www.theremino.com

It is an Italian Open source Project aiming to create a simple system to control I/O informations without the need to learn a language as is the Arduino one.
So any developer/user must concentrate only on its own programming language/preferred software without the need to learn a dedicated language (as in Arduino)

From Theremino website:

Quote:
Theremino is an Open Source system (Hardware and software), that connect computers with the real world.
Applications range from music, teaching, scientific research. Unlike similar systems (eg Arduino), the system works
as you turn it on, and does not require the firmware programming (as is for Arduino).
More...
Quote:
Theremino is a middle ground between Arduino and the LEGO and is aimed primarily at people who are not electronic engineers and programmers.
We engineers tend to forget it, but the people who deal with other, are something like 90% of the world population.
And it is really like this!!!

I am not skilled in electronics but with a huge help from Theremino team (Livio) and many people on our forum I was able to make a fully functional CNC controller, that can be used for any CNC machine with maximum 5 axis!!
This controller can control Hot wire temperature by mean of a PWM output.

Theremino must always be connected to a running PC with a software that performs some job with theremino itself (main difference to Arduino).
The interface to the theremino hardware and all the peripherals connected to it is the Theremino HAL, a piece of software that control what comes/goes from/to the software running on a windows based PC and the Theremino MasterDIL.

This system (in my setup) is made by a Master (called MasterDIL)



MasterDIL V4 offers 12 pins that phisically are places where you connect your actuators (pin out) or sensors (pin in).

Those 12 pins are under thereminoHAL control who either receives a command by a software and direct that command to an OUT PIN or receives a signal by a sensor (INPUT PIN) and drive the information to a software...
More or less (and really simply speaking) it's like this..
For more informations here is the HAL Documentation
There are 8 OUT PINS (4 step and 4 dir) in a CNC like the one I'm describing here.

Where can you buy it?!?

If you live outside EU you can buy a MasterDIL V4 here

For EU people this is the EU Warehouse

For ten bucks you have your super-duper controller!!

With this controller you can build many really amazing things!!
Like a radon measurement device (if you cut your RC planes in your basement..)

Banana keys!
BananaKeys and Pacman (0 min 27 sec)


Many other things...


But dealing with CNC machines all you need then are four stepper motors, four drivers (you'd better to buy one or two as replacements..) and I used a prebuilt shield..
And of course a power source for your steppers...

I bought:
  1. One MasterDIL V4 (12 pins)
  2. One CNC Shield V3 (you can find everywhere on the web - I bought mine on ebay for may be 6 euros)
  3. Four Pololu drivers DRV8825 (you can find them in Thereminostore.com - again buy some more - they can explode in handling)
  4. Four Stepper motors (Nema 17 -17hs4401n - in my setup)
  5. One Switching power unit (S-201-24 - 24V 8.3A in my setup)


On the CNC you must:
  1. Connect Enable/Gnd to a GND on the Masterdil
  2. Connect the masterdil pins 1,3,5,7 to the X,Y,Z,A STEP pins, then connect the masterdil pins 2,4,6,8 to the X,Y,Z,A DIR pins.
  3. Connect Logic/Gnd to +5V/Gnd on masterDil (I used +5V/gnd below pin 1)
  4. Put 2 jumpers between the 2 couple of pins to use A axis as autonomous axis
  5. Connect the two phases of each stepper to A1/A2, B1/B2
  6. Put a jumper on the M0/M2 jumper to set microsteps (M2 in my setup for 16 MSt)
  7. Connect your power source (max 36V) to its connector on the shield (24V on my schema)

EDIT (thanks to kojderek)
EN/GND must go to a GND or to a pin whose state is OFF on masterdil.
In my setup pin 9 on masterdil isn't assigned to any IN/OUT in theremino HAL (unassigned) so it's state is OFF. This way CNC is in enable state.
Or you can use PIN 9 in HAL to turn ON/OFF your stepper drivers..








My setup is like this! (without drivers installed yet..)



After you connect everything it's time to regulate the drivers output current.

I followed this Pololu video and their formula:
Quote:
Current Limit = VREF × 2
Setting the Current Limit on Pololu Stepper Motor Driver Carriers (9 min 3 sec)


And the specs of Nema17


According to this table my Stepper have 1.7A max current
I want to set drivers max current to 2/3 stepper's max current so 1.2A more or less

This way I will have VREF=1.2/2=0,6V

So I set one driver at time on the CNC shield and measured VREF on top of the pot screw, like shown on the above video

This is the way I did it (don't consider all drivers set in place..)
Be careful because if you make a short circuit with power on the driver may explode..



This is my CNC Controller completed


And now all is set up!
You're ready to go!!
Good night
Last edited by pieri70; Jan 04, 2017 at 01:32 PM.
Dec 17, 2015, 12:38 PM
Registered User
So now you have your 4 axis foam cutter on your bench ready to move!
You need ThereminoCNC to move your axis

Here is the link to the ThereminoCNC V4.1

To use it simply unzip it in a folder and run Theremino_CNC.exe



Always control on the official page, under download section, they often change ThereminoCNC to improve its functionalities.

Here is the English Help

ThereminoCNC control your CNC machine by mean of Theremino HAL (Hardware Abstraction Layer), so each time you run ThereminoCNC another software is launched, that is
\Theremino_CNC\Theremino_HAL\Theremino_HAL.exe


Here you can find informations on Theremino Hal
You can find the Help in your language in the "\Theremino_CNC\Theremino_HAL\Docs\" folder

On the HAL you must give a name to your Masterdil, clicking on "Name" Button and saving it.
This way every time you connect this MasterDil it can be recognized among others (you can have many masterdil connected at the same time to make different tasks..).
Then you must assign a SLOT to each pin.
A slot is a piece of memory where a software (i.e. ThereminoCNC) write/read a value.
In Appendix 9 of ThereminoCNC Help you can find a list of slots and their function
Quote:
Appendix 9 - Input / Output Slots
01 OUT - Axis X - Destination (mm)
02 IN - Axis X - Distance from destination (mm)
03 OUT - Axis Y - Destination (mm)
04 IN - Axis Y - Distance from destination (mm)
05 OUT - Axis Z - Destination (mm)
06 IN - Axis Z - Distance from destination (mm)
07 OUT - Axis A - Destination (mm)
08 IN - Axis A - Distance from destination (mm)
09 OUT - Axis B - Destination (mm)
10 IN - Axis B - Distance from destination (mm)
So in the figure above there are all 4 stepper motors (dir/step) with assigned slots.
On PINS 5 and 6 I set the B Axis slots (9 and 10) and on pin 7-8 I set A Axis slots (7-8). The other pins are X,Y axis slots.

To assign a pin type to a pin just select a pin and on the right click the "Pin type" and a dropdown list appear.
Choose "Stepper" from the list. As you choose Stepper for ex. pin 1, automatically pin 2 becomes "Stepper_dir"



For each pin select which slot to be assigned according to the above list (Appendix 9)

After you set all your pin you must specify how many steps/mm your axis have.
In my setup I use 16 microstep and 1,25mm pitch screws, my steppers are 1.8°/step (200steps/turn)
So steps/mm will be 200*16/1.25=2560 steps/mm



In the above figure there is a stepper pin for X axis (slot 1).
1000 means=1000 and 0 means mm =0 can be inverted to reverse the movement of your stepper motor!!
Don't touch "response speed" let it = 100 (it's a filter - read HAL help for infos).

Max sp. and max acc are maximum speed and acceleration in mm/min and mm/s/s your motor can run before reach its limits (it starts grinding).

You must regulate these values trying to move fast your axis (Jog at full speed) until your motor begins to loose steps..
The max acceleration can be found moving forward/backward continously.
Again at max accel your stepper motor starts grinding.
Then you set these values at least 20% less for safety reason.

As soon as you set all your pins and regulated max speed and max accel you are ready to use ThereminoCNC!!!

Here is a first video with only one pair of axis working, the second one had only the Y axis controlled (it was a sketch for a XYZ CNC mill..)

ThereminoCNC CNC foam cutter (1 min 20 sec)


So,
run ThereminoCNC, this is its interface



In the figure above there is GCode loaded in ThereminoCNC and on the right you can see the resulting Path.
It's the root section of a sweeped (30°) flying wing made using GMFC and Cut2G.

Cut2G is a software that can convert cut files produced by GMFC into GCode.
You can find it googling around..

Cut2G must be set like this (except for metric/imperial units):



So in the above picture I set millimeters as units, Inverse time (feed is calculated so movements on tapered wings are performed synchronously), I don't use heat control, I want constant velocity (for smooth surfaces), I'll like comments to better understand Gcode, And my Axis are XY - AB.

As you can see on the bottom-left part ThereminoCNC shows XYAB keys and their value.
If you write a value in an axis control that value will be it's position in millimeters.
If you press an axis key you set that axis to zero!

On the left part you have your GCode (you can edit as you like) and buttons to start/pause/stop your job.
There are also keys to load, rewind, make characters bigger/smaller ecc ecc.

On the right part there is the toolpath (your whire path), axis position values,
Rapid (jog speed - never set it bigger than your slower stepper - see HAL Max speed)

You can switch between view (Root/Tip 2D view)



All you must do is load your Gcode, translate it to zero ("Tools > Translate to zero (x/y a/b)"), move your whire to the zero point near your foam block and start your job!

That's it!!

See you
Last edited by pieri70; Dec 21, 2015 at 03:32 AM.
Dec 17, 2015, 12:39 PM
Registered User
This is the last part of my CNC system construction, that is foam and kerf calibration.

Any kind of foam and each bow/wire you use need a calibration for temperature and kerf calibration.

Too much temperature/too slow speed will burn your piece of foam and in opposite situation your wire will touch foam and will bend, so you will have the extreme of your foam block correspondent to the desired shape but in the centre you will not have a correct interpolated surface...

To calibrate Speed vs Temperature I used a block of desired foam, 60x6x10 (LxHxD) and I made horizontal slies about 6-8mm thick.



Each time I moved the wire at a desired height, horizontal, near/parallel to the block of foam and set axes to zero.

Then i used a simple Gcode to make my wire travel horizontal for 200mm

Quote:
%% SET LENGTH UNITS G21: MILLIMETERS
G21

%% SET PATH CONTROL MODE G64: CONSTANT VELOCITY
G64

%% SET DISTANCE MODE G90: ABSOLUTE
G90

%% SET FEED RATE MODE G93: INVERSE TIME MODE (MOVES PER MINUTE)
G93

%% This Feed is for 200mm@2mm/s speed :

F0.6 X200 Y00 A200 B00
Here you can find a spreadsheet with some formula to get Gcode from travel lenght and speed.

Themperature wasn't directly measured, instead I measured Volts coming from the wire power source.

The job is to start cutting at a given voltage and decrease it until the foam block start to move pushed by the wire. The foam block must be free to move, without any weight applied on its top, or any impediment..
When the foam block start to move you read the voltage on your multimeter. Add 0,2-0,3V and this is the voltage to supply to your wire (eg given lenght and diameter) to cut at a given speed.

This is a little amount of slices..



And this is the result of my Voltage vs Speed (mm/s)



This the Plot



As you can see, with my setup there is around 1,5-2V each 0,5mm/s increase.


Once you get the correct Voltage for each speed, you can perform Kerf calculation.
To calibrate kerf I used GMFC 30 day demo software.

In GMFC you must configure your table

Here is my setup



I left 200 steps per revolution
I set 1.25 in screw thead (my screw is like that) I set step lost to 0 as with my spring setup (see above) and stepper precision is like this.
Then I played around with other parameters with no influence on cutting performnce.

It's important to set the correct dimensions (X,Y travel and suupport distance) , in particular support distance is crucial because GMFC calculate the correct speed considering this parameter.

Then go to foam management, select target speed and set root/tip kerf to zero



In above figure speed is 2,5mm/s and kerf=0

Then go to "Current panel configuration" and set parameters like this



Use your panel span and thickness
Select different root/tip and x centered

In root and tipo airfoil select "Rectangle 2 sur 1"
Set 80 root chord and 40 tip chord
Then set other parameter to center your cut

You should have a layout like this



Then go to to "panel cut", set block placement, the foam you set above and select "cut to file"



If you select "block centered in Z" under Block Position, be sure the middle span of your block correspond to the middle point between your wire support!!!

If all is OK you get a green message in the lower right part of the Panel cutting mask

Save your .CUT file somewhere and use Cut3G to convert it in standard GCode with these settings:



Load Gcode in ThereminoCNC and go to tools "Translate to zero x/y a/b"

Move your wire to the bottom part of the foam block, turn on your wire power source, set the correct voltage for your speed (see above) and click on "start"

If you have a gamepad you can use it to move your axis (read the ThereminoCNC manual how to use it)

ThereminoCNC joy pad control (0 min 14 sec)


Here is an example of a "trapeze cut" @3,5mm/s

CNC Foam Cutter Theremino CNC (1 min 22 sec)


After you and your cut take the two pieces and measure the external dimenzion on root/tip
The difference between desired (80/40mm - see panel configuration) ad cutted pieces is the kerf (root and tip).
For example if you measure 78.8mm for root lenght and 39mm tip lenght, then your root kerf is 1,2mm and tip kerf is 1,0mm.

Again, choose your foam management and enter these values for root/tip kerf.
If you want to be sure of the result try to cut other two blocks and measure again kerf.
Eventually modify it again in foam management.

Make this process for any speed you want to calibrate.
With my CNC I got 0,1mm precision on 80mm square block!!!!

That's it
Now you have your CNC set to cut your beloved foam wings.

Here are some example, i just cut one or two of them.






Here the surface


Bye Bye
Last edited by pieri70; Dec 21, 2015 at 01:44 PM.
Dec 22, 2015, 01:46 PM
Registered User
To complete this thread I will discuss briefly about DevWing Foam the Cam software I decided to buy after my early test with GMFC.



I'm beginning to use it, I just designed ONE wing and I thought to describe it in a separate discussion, but I think This is the right place to start writing about it.

GMFC is relatively simple, but has many drawbacks.
First of all it is designed to work with its dedicated Parallel controller (MM2001), if you want to buy an official USB controller you must buy the interface and the license to make it work (G.CC+License are almost 100E).
So If you consider the amount of money to buy a full GMFC license (GMFC Expert 300Euros) and its interface (mm2001 E? plus GCC USB and License) you'll rise surely more than 400-450E..

This was out of budget for me.
So I bought Devwing Foam for 95E 10E for Theremino MasterDil V4 and that's it!!

I'm also testing DevCNC Foam that is a full featured CNC control software, many more features than ThereminoCNC. The code execution is good in both systems anyway if you choose Inverse Time for Feed in GCode!

Then some other problems in GMFC, like the inability to rotate the foam block on Y axis (with wing profile reprojection on X axis), big help when you cut wings with big sweep angle and a lot of taper..
From THIS POST onward my discussion on GMFC Official thread.

So I will explain how to build a sweep flying wing like this with DevWing Foam.
Please consider that I built just one wing with this software, so tell me if I'm wrong in some description, I'm learning to use it..



As you can see this wing has 19.3° angle on trailing edge, so with GMFC you must cut as case "B" of this diagram.

I want to cut like case "A" due to limitations in my X axis travel.. With devWing Foam you can. It takes care to rotate Root Tip airfoils.



This is the Projet management window, here you can choose to build a new project or to modify your already created ones, and also you can print, view in 3D and create the Gcode for your wing.



Let's start with a new one

In general settings you give your wing a name and description, here you choose Root dimension and half wing lenght.
Distance between half wing is the distance between root sections (e.g. if you have a fuselage).
Numer of panels if you know you have different sections along your half wing (you can add them later).
In any window just click "?" and the help relative to your position will open..



Then you can import a background image as reference for your wing build.



Here you define your wing planform with sweep, tip lenght and you can decide if you want your panel to be splitted in two ecc..



In the next window you decide if you want your panel to be splitted in any number of panels you want, with desired dimensions (didn't use it in this build).



In the next window you choose which airfoil to use on root/tip of your panel/panels.
You can choose dihedral and washout angles and many other parameters (I didn't use them yet..)



If you click on select airfoil you get a huge list of airfoils. You can search and filter for string or by parameters..



Now you can also begin to see your wing in3D mode...

DevWing Foam 3d Wing (0 min 21 sec)


Next step is wing sheetings. You can decide their thickness and different settings for different panels.



Then You have Leading Edge, Trailing Edge and Spars, all fully customizable.
I didn't use them yet so I'll postpone their descriptions





Next step is the definition of Slots and ailerons/Flaps cut, I used a "V" shaped cut for my flaperons so I added a new element to my panel. I choosed to cut the aileron and how distant was the hinge border from Trailing Edge at root/Tip, of course you can see how it works in 3D





DevWing foam V Cut Hinge ailerons (0 min 21 sec)


Then you can select if you want your panel to be drilled with holes to lighten it



Next are wooden ribs for Root/Tip and templates to control your cut (didn't use them right now..)




Then you get all your Projet Wizard complete!



You can start to think the GCut strategy, but I'll discuss about it in next post

Bye
Last edited by pieri70; Dec 22, 2015 at 05:25 PM.
Dec 22, 2015, 01:48 PM
Registered User
So, after you finished your wing project select it and click on "Create a foam cutting Project from..."



In the resulting mask you must add your wing block to the foam block.
You can add more than a wing block to a foam block, so they can be cutted all in a single run



Then you choose which speed and kerf to apply to your cut.
Different speed and kerf can be used for different wing block in the same foam block and for different elements to be cutted in a given wing block


It's really important to set the cutting strategy at this point!



You can choose to cut your wing as a single piece (default) or to split horizontally in two along mean line or chord..
You choose if you want an horizontal cut to separate your shells, you decide how to cut your LE/TE and most important in sweeped/tapered wings you can choose to rotate your block on the Z axis with align to Trailing Edge (or LE or mean chord)!!



This way you reduce your X travels and the software take care to reproject root and tip airfoil!!


This is the rotated foam block as seen from the top



Then you can simulate your cut with a click on "3D Preview of selected block"
In this video a cut simulation (I didn't rotate block on Z axis..)

Devwing Foam cut symulation (0 min 43 sec)


Then you must set the parameters of your cutting machine (Travel X/Y and distance between carriers - on the left in the below image) and the placement of your foam block



Then side shaping to cut root and tip for wing sweep



Then you can save your cutting project in many ways
In my case I used "Create 4 axis Gcode fo both carriages" to cut with ThereminoCNC!

Or You can create the right Gcode for DevCNC Foam

Last edited by pieri70; Dec 26, 2015 at 04:56 PM.
Dec 26, 2015, 04:47 PM
Registered User
Once you created your GCode you can use DevCNC Foam



Its GUI is simple
On the Upper-left part there are buttons to Load Gcode and run it (start/Pause/Stop/Rewind)

Below there are left and right axis positions and speed (both as carrier "SC" and foam "SF")
With a click on the pencil you can set Origin, go to zero and set a desired movement (absolute and relative)

Then arrow keys to move your wire

Below these you can set the Jog Speed and decide if you want your left and right axis to move together during manual jog

Below there is emulation to play with Gcode and the 3D model on the right, without having your axis moving around..

Then buttons to set origin, move to origin etcetera.

On the center there is your loaded GCode. It can be edited and saved.
On te right the resulting Cut in 3D..

Under Settings it's important to select the correct Theremino Master



Then you must set your motors as for ThereminoCNC



Then speed



Gcode (axis and feed - if not set in GCode)



Machine size and foam (if not specified in GCode)



Then Limits and hot wire management (I didn't use them)
Keyboard and Gamepad settings (really useful!!!)

And Of course Units



And that's it!!

Hoping this guide will be a good reference for someone starting with this stuff like me.

Ciao!
Last edited by pieri70; Dec 26, 2015 at 04:52 PM.
Dec 27, 2015, 03:57 PM
Registered User
Just setting up my foam cutter now. Went the Smoothstepper with Mach3 route first. For such a complex program I found it was till no able to do what I consider simple things that I tried to program with macros. It stalled me for months because of this. Tried other programs etc. Tried Theremino yesterday, so simple and effective. I love the approach they took it. I will be able to use it for other projects.

I will probably go the Dev Software route.
Dec 27, 2015, 04:05 PM
Registered User
Yes is a nice and cheap controller (10$ in comparison to more than 180$ Smoothstepper unit) and ThereminoCNC is a good choice as open source software, in my test it was working with no problem!
Devwing foam and devcnc foam are great softwares, you must pay for them but it's a little amount of money in comparison to what you pay for other commercial solutions...
These are anyway my actual choice because of powerful features and easy use.
Bye
Last edited by pieri70; Dec 28, 2015 at 01:17 AM.
Jan 22, 2016, 12:35 PM
Registered User
Wonderful tutorial, Pietro. Ande very well explained with a lot of pictures. Great job!

I wish I had seen your approach before I started out to go the Arduino way. Seems to be a lot easier. Anyway, I will continue my Arduino based cnc foam cutter, as I have got as far, as I am now.

I have a question:

Can you tell me, if I need DevWing Foam when I already have Profili Pro? I can generate G-code with Profili Pro, so does Dev Wing Foam make any advantage?
Jan 22, 2016, 03:53 PM
Registered User
Hello Soren
thanks! I thought this topic didn't raise any interest..
Theremino is super easy with CNC. No need to mess around with arduino code, just plug and play.
Also ThereminoCNC is supersimple and free.

I didn't use Profili Pro so I'm not the right person to ask. But Devwing Foam is expecially made for foam wing design and gcode generation. It has a lot of tricks to set the cutting strategy.

Best way is to try it, install and try to design your wing. I think it should work with restricted gcode generation.
Bye
Pietro
Jan 23, 2016, 03:46 AM
Registered User
Quote:
Originally Posted by Søren Vedel
Wonderful tutorial, Pietro. Ande very well explained with a lot of pictures. Great job!

I wish I had seen your approach before I started out to go the Arduino way. Seems to be a lot easier. Anyway, I will continue my Arduino based cnc foam cutter, as I have got as far, as I am now.

I have a question:

Can you tell me, if I need DevWing Foam when I already have Profili Pro? I can generate G-code with Profili Pro, so does Dev Wing Foam make any advantage?
devWing Foam offers a lot of added features, like (brief list):
- multiple panel managing, you can draw the full wing
- free wing plan shape, non only tapered
- a lot of improved elements like spars, lightening holes, or added as aileron slots
- optional inline cutting of spars and of other elements
- optimized cutting for external shell (if you need use them as a mould)
- optional cutting of internal element with a cut along the chord line or mean line. No external entry/exit are applied, and the kerf is also applied to this cut, so you can just glue together the upper/lower parts
- multiple panel cutting
- a lot of cutting strategies for the outer contour and the elements
- better speed management by the inverse time mode, for strong tapered cuts
- 3D previews of all parts and cutting
- squaring block cutting
- wizard with advanced navigation (not only previous-next page)
- automatic kerf for all items

regards
Stefano (proud devWing developer )
Mar 01, 2016, 06:57 AM
Registered User
Hello
just a quick update to my machine
After my first cheap build solution I decided to switch to V-Slot extruded profiles with V-Wheels





At first I tried the belt/pulley solution with T2 belt and 16 teeth pulley





This solution wasn't good because stepper motor and 32 microsteps gave lots of vibrations @2-3mm/s cutting speed.
So I decided to adopt my old system..

Here is the anti back-lash solution: two long nuts, a threaded bar and a spring




On one nut I made an incision so a bended M3 threaded bar could insert into it



Then I bent a piece of M3 threaded bar




And then this is the result.




The second nut can be firmed with a zip tie.
Here some steps in my upgrade, self explaining..















Here a short video of the first test
Threaded bars are wobbling a little, but X axis can be fixed to your working bench, so no problem arises to your cutting path

Theremino cnc foam cutter v-slot upgrade (1 min 18 sec)


Bye
Mar 02, 2016, 03:57 AM
Registered Slopeaphile
awmeade's Avatar
Really nice. I must build one of these this year
Mar 02, 2016, 04:37 AM
Registered User
Thanks Awmeade
my suggestion is to go with Theremino
Really simple to use and configure, no mess with code or slow connection/loosing steps etc..

bye