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The Mini CNC project is a complete set of plans and instructions on how to build a 3 axis CNC machine that is functional and also precise. The Mini CNC is very simple and easy to build and if you have all the materials and parts prepared you should have it ready to work in less than 5 days.

 

I wanted and also needed to build this Mini CNC machine so I can make faster and more precise the parts that I need for my other home projects.

Step 1: Mini CNC Specifications

The working area of the machine is X=450mm (approx. 17.5 inch) and Y=250mm (approx. 10 inch) and can mill parts as high as Z=110mm (approx 5 inch).

The maximum milling speed on X an Y axis is 2400mm/min. and on Z axis is 1800mm/min.

The resolution of each axis is 1/50 or two hundredths of an mm and one axis revolution means 4 mm of movement.

The router used for this CNC is a Kress 1050.

The number of parts used for building this Mini CNC machine is 42 excepting screws and nuts.

Step 2: Required Tools and Skills

For this project you will need to have a set of screwdrivers and a set of hex keys or Allen keys, a drill for some extra holes, metal cutting saw to cut some custom parts, soldering station or soldering gun join the wires so they`ll have a good conductivity , and a multimeter.

You should have knowledge of basic electronics, how to solder and how to use a multimeter

Step 3: Ordering Components

All the parts used to build were bought from local dealers, so i suggest you do the same if it`s cheaper (parts + transport). If not you ca find all the part on eBay.

The trapezoidal cylindrical nut was made in a local workshop.

Step 4: Mechanical Components - Aluminum Profiles

The frame is made of aluminum profiles and the part are:

-          X base parts          2 pieces of 400x120x30mm

-          Y frame parts        2 pieces of 400x120x30mm

    1 piece   of 380x60x30mm      cost: 13.16$

-          Y carriage              1 piece   of 120x120x30mm

-          Z carriage              1 piece   of 120x120x30mm

-          Z frame parts         2pieces  of 120x60x30mm

-          machining the aluminum profiles    


The product code for ITEM 120x30 aluminum profiles is 0.0.419.04 and for the ITEM 60x30 aluminum profiles is 0.0.419.04

Step 5: Mechanical Components - Shafts, Bearings and Leadscrews

1)      Precision steel shafts:

-          Ø20mm precision steel shafts for X axis (cut from 1 piece of 60 inch=1524mm shaft)

·          2 pieces of 600mm long

-          Ø16mm precision steel shafts for Y axis (cut from 2 pieces of 30 inch=762mm shaft)

·         2 pieces of 390mm long 

-          Ø16mm precision steel shafts for Z axis (cut from 2 pieces of 372mm shaft left from the Y axis shafts)

·         2 pieces of 300mm long

-          machining the precision steel shafts

·         6 pieces                                  

2)      Ball bearings/bushings

-          Ø20mm (Ø32 outer diameter) ball bearings/bushings

·         4 pieces

-          Ø16mm (Ø26 outer diameter) ball bearings/bushings

·         8 pieces

3)      Trapezoidal lead screws cut from a 1500mm long trapezoidal lead screw:

-          Ø16mm  trapezoidal lead screw with 4mm pitch for X axis

·         1 piece of 657mm long

-          Ø16mm  trapezoidal lead screw with 4mm pitch for X axis

·         1 piece of 447mm long

-          Ø16mm  trapezoidal lead screw with 4mm pitch for X axis

·         1 piece of 357mm long

-          end machining for the trapezoidal lead screws in a local workshop

·         3 pieces          

 

4)      Trapezoidal cylindrical Nuts that I made on a lathe in a local workshop:

-          Ø16mm with 4mm pitch nut

·         1 piece with Ø32mm outer diameter and 32mm long

-          Ø16mm with 4mm pitch nut

·         2 pieces with Ø24mm outer diameter and 24mm long

Step 6: Electronic Components - Motors

The motors chosen for this project are 3Nm 8 wire stepper motors that can be wired as unipolar or bipolar, depending on everyone’s choice or what driver you have (unipolar or bipolar).

   -  3 pieces of 3Nm stepper motors    

A unipolar stepper motor has two windings per phase, one for each direction of magnetic field. The motor has only five leads.
Bipolar motors have a single winding per phase. The current in a winding needs to be reversed in order to reverse a magnetic pole. There are two leads per phase, none are common.


The difference is: “Unipolar and Bipolar Half Coil, because we're using less turns, doesn't give us great low speed torque, but because of the low inductance, holds the torque out to high speeds.
Bipolar Series uses the full coil so it gives very good low speed torque. But because of the high inductance, the torque drops off rapidly.
Bipolar Parallel also uses the full coil so it gives good low speed performance. And its low inductance allows the torque to be held out to high speeds. But remember, we must increase current by 40% to get those advantages
.”
 

Step 7: Electronic Components - Motor Controler

The stepper motor driver used is a unipolar 4 axis driver for 5A/phase motors, the input power is 20-40V DC (local shop). 

Electrical properties
Input Power 20-40V DC
Stepper motor drive current 1.5A - 5A/phase
Compatible Stepper motors 2 or 4 phase, 6 or 8 lead stepper motors, 5A max.
Dimensions 18 x 12 x 6 cm (L x W x H)

This board allows you to control 4 stepper motors, as well as receive input from two limit switches/ motor and from an emergency stop button and has a relay spindle interface  for spindle motors.

Step 8: Power Supply Components

The power source contains one 600W toroidal transformer, one 50Amps rectifying bridge and one 20000µF capacitor.


 

Step 9: Motor Controller Case

For the motor controller case I used an old Keithley236 source measure unit. I have got out all the guts of the old thing to make way for the  new motor controller and power supply.


Step 10: Electrical Wiring - Power Supply

The input of the transformer is for 230V AC current and has two 21V AC current outputs. The outputs are connected in parallel and then they go in to the rectifying bridge. The rectifying bridge transforms the AC current from the input into DC current on the output. The positive and negative output of the rectifier is connected to the positive and negative of the 20000µF capacitor that smooth-ens the current. From the capacitor you can now connect to your drivers DC input.

Step 11: Electrical Wiring - Motor Controller

An 8-lead stepper is  like a unipolar stepper, but the leads are not joined to common internally to the motor. This kind of motor can be wired in several configurations:

- Unipolar.
- Bipolar with series windings. This gives higher inductance but lower current per winding.
- Bipolar with parallel windings. This requires higher current but can perform better as the winding inductance is reduced.
- Bipolar with a single winding per phase. This method will run the motor on only half the available windings, which will reduce the available low speed torque but require less current.

The motors are unipolar motors so you will need to run 5 wires from a motor controller to each motor. The two so called common wires from the motor controller are connected to the four (red, green, yellow and black) wires motor, making a thick common wire.

Step 12: Testing the Stepper Motors


In this test i tried to connect the motor with a serial cable but it was to thin for the current that was passing it so it was heating very fast. But the connections were good so I just replaced the cables back with thicker ones, as you seen d in the previous steps.

Step 13: Machining Mechanical Components - Aluminum Profiles

Before mounting all the parts well need to make some machining to the aluminum parts.

The drawings that show you how to modify this parts are in dxf and pdf format so feel free to use them.

The modifications that you`ll have to make must be done on a milling machine and not by hand. You will have to make some holes thru which screws and trapezoidal lead screws cross (X Base, Y side parts, Z parts), some 5 mm deep holes in which the precision steel shafts are centered, some 5 mm deep holes in which the trapezoidal lead screws end bearings stand (X Base, Y side parts, Z parts). You will also need to make 3 holes in the Y cross section, two of them for the linear ball bearings and one in center for the trapezoidal nut. In the two pieces of X Y carriage profiles you will have to make 5 pockets in witch will sit tight the 16mm linear ball bearings and a trapezoidal nut.

The machining of these parts was made in a local workshop on an old Conventional 3-axis vertical milling machine.

Step 14: Machining Mechanical Components - Linear Shafts


For the precision steel shafts you will have to make some end screw holes so you can fix them on the aluminum profiles frames. It will be indicated that you make that hole on a lathe., because it will be centered and coaxial with the shaft.

Step 15: Machining Mechanical Components - Trapezoidal Lead Screws and Nuts

The next step will be  to machine the ends of the trapezoidal lead screws so you can mount the bearings.  This will also need a lathe to make the ends more accurately so that the bearings wont be moving in all directions.

The trapezoidal nuts were made from scratch, out of POM or Polyoxymethylene that is "an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability "
There are two types of 16mm trapezoidal nuts, first one has 32 mm outer diameter and 32mm in length (one piece) and the second one has 24mm outer diameter and 24 in length.


Step 16: Machining Mechanical Components - Ball Bushing Supports

Finally the last component that you will have to make is the X ball bearing support.
You will need two pieces , one for each part of the X axis.
You should do it on a 3 axis milling machine.

All the machining operations were made in a local workshop.

Step 17: Mechanical Assembly - Z Axis

For this axis you will need:

-           1 piece of 120x120x30 aluminum profile

-           2 pieces of 120x60x30 aluminum profiles

-          2 pieces of Ø16 by 300mm long precision steel shafts

-          4 pieces of Ø16mm (Ø26 outer diameter) ball bearings/bushings

-          1piece of Ø16 by 357mm long trapezoidal lead screw

-          2 pieces of 6000zz ball bearings

-          1 piece of Ø16 by Ø24mm outer diameter and 24mm long trapezoidal nut

-          4 pieces of M5x40mm screw

Now will mount the ball bushings in all 4xØ26mm holes of the aluminum profile them will mount the trapezoidal nut in to the Ø24mm hole. Next mount the trapezoidal lead screw in to the trapezoidal nut and then mount the 2 pieces of 6000zz ball bearings in to the Ø26mm hole of the 120x60x30 aluminum profile. Insert the 2 shafts into the ball bushings and then mount the 2 pieces of aluminum profiles at each end of the shafts and trapezoidal screw.

The last operation is to mount the screws in to the shafts hole to fix the whole assembly.

Step 18: Mechanical Assembly - X Axis

For this axis you will need:

-          2 pieces of 400x120x30 aluminum profiles

-          1 piece of 380x60x30 aluminum profile

-          2 pieces of Ø20 by 600mm long precision steel shafts

-          4 pieces of Ø20mm (Ø32 outer diameter) ball bearings/bushings

-          1piece of Ø16 by 657mm long trapezoidal lead screw

-          2 pieces of 6000zz ball bearings

-          1 piece of Ø16 by Ø32mm outer diameter and 32mm long trapezoidal nut

-          2 pieces of ball bushing supports (see drawing)

-          4 pieces of M5x40mm screws

-          2 pieces of M5x60mm screws (for the ball bushing supports)

For start mount the ball bushings in the 2xØ32 holes of the 380x60x30 aluminum profile and then the trapezoidal nut in the Ø32 hole from the middle of the aluminum profile.

Mount the 2 pieces of 6000zz ball bearings in the 2xØ26 holes of each 400x120x30 aluminum profiles and 2 pieces of Ø20mm ball bushings in to each ball bushing supports.

Now insert the shafts in the mounted ball bushings and the trapezoidal screw in the trapezoidal nut and then mount the 2 pieces of 400x120x30 aluminum profiles at each end of shafts and trapezoidal screw.

Fix the shafts on to the 400x120x30 aluminum profiles with the 4 pieces of M5x40mm screws.

Step 19: Mechanical Assembly - Y Axis

For this axis you will need:

-          2 pieces of 400x120x30 aluminum profiles

-          1 piece of 120x120x30 aluminum profile

-          2 pieces of Ø16 by 390mm long precision steel shafts

-          4 pieces of Ø16mm (Ø26 outer diameter) ball bearings/bushings

-          1piece of Ø16 by 447mm long trapezoidal lead screw

-          2 pieces of 6000zz ball bearings

-          1 piece of Ø16 by Ø24mm outer diameter and 24mm long trapezoidal nut

-          4 pieces of M5x40mm screws

The first thing you`ll have to do is to mount all the Ø16mm ball bushings and the Ø16mm by Ø24mm trapezoidal nut in the 120x120x30 aluminum profile like in step 6 and then insert the shafts in the mounted ball bushings and the trapezoidal lead screw in the trapezoidal nut.

Mount the 2 pieces of the 6000zz ball bearings in the Ø26 hole of each 400x120x30 aluminum profiles.

Next mount the 400x120x30 aluminum profiles at each end of the shafts and fix them together with the 4 pieces of M5x40mm screws.

Step 20: Mounting All the Axis Together

Now will have to mount all the axis together to complete the mechanical assembly.

First mount the Y axis on to the X axis by fixing together the 2 pieces of 400x120x30 aluminum profiles with the 380x60x30 aluminum profile and the 2 pieces of ball bushing supports.

Next fix together the Y axis with the Z axis by mounting the 120x120x30 aluminum profile of the Z axis over the 120x120x30 aluminum profile of the Y axis but at a angle of 90º.

Step 21: Mounting the Motors

Now will have to mount the stepper motors on to the CNC machine, but first we need to make some motor supports.

I used a threaded rod and I cut it in smaller pieces to make the support for the motor. Over the pieces of  threaded rod I have put some smaller tubes of aluminum that will act as spacers between the motor and the CNC frame.

Now mount at one end of the rod, a nut, and place the rod with the nut in to the 4 mounting holes of the motor.

Between the motor and the lead screw I have put a rubber hose and over it two hose clamps that will act as a coupler.

Now over the rod put the aluminum spacers and mount the motor on the frame with the rods in to the 4 holes in the frame.

Repeat this for all the 3 motors.

Step 22: Mounting the Cable Suports

I have made  the cable supports from U shaped aluminum profile  and two steel corner braces.
For the X axis I cut the profile to the required length and mounted the two steel corner braces at each end of the profile.
After I mounted the steel corner brace onto the profile I mounted the cable support on the CNC machine with 4 screws ant 4 t-nuts.

Same goes for the Y axis only there I did not used steel corner braces, I just mounted the profile on the CNC with two screws and two T-nuts.

Step 23: Motor Wire Conections

As I was saying at step 11, we will use a unipolar wire configuration, this means that will have 5 wires.
Now the 8 wires that the motor has are:
First coil - A is yellow/white and it is the start of coil, neg A is yellow and is the end of coil;
Second coil - neg C is red and is the start of coil, C is red/white and is the end of coil;
Third coil - B is green/white and is the start of coil, neg B is green and is the end of coil;
Fourth  coil - neg D is black and is the start of coil, D is black/white and is the end of coil.

Now to make 5 wires from 8 wires will have to connect all the neg wires between them and make a single wire.

Now we have 5 wires that we can connect to the controller driver board.

The cable wires between the motors and the controller are 1.5mm thick so that they wont heat up.
When you connect two cables, solder them together because the connection is stronger and insulate them with shrinkable plastic tube.




Step 24: Limit Switches

Home switch is for mechanically setting the machine's reference position when you power it up.

Also the limit switches are used to prevent you running the table either off the end of the ball screw or into the ball screw bearing housings.

As you can see i have mounted the Z axis limit switches right on to the aluminum part using two drilled holes and threading them.
The Z axis hast two limit switches, one for going up and one for going down. The two limit switches are connected in series and then connected to the controller thru a serial cable.

The Y limit switches needed some extra support so I had to  make 2 supports from a piece of aluminum.
 The X limit switches are mounted on the X axis cable suport.

Step 25: CNC Software Configuration

Now in ordertoputintooperation and start cutting and drilling with this CNC machine we have to configure the CNC software (in my case Mach3)

First of all I will set the native units to mm, because I am using the metric coordinates.

Next will have to configure the motor outputs from the ports and pins menu. As you can see I have entered the corresponding pin number for every motor step and dir. This information comes with the controller driver board. 

Now that we have the pins configured we have to configure the limit switches inputs and the input of the E-stop. This information also comes with the controller driver board.

After configuring all the pins we have to setup the motors. Access the Motor tuning menu under Config  menu and fill the steps /mm box with how many steps must your motor to turn so that your gantry moves 1mm (mine dose 50 spets/mm because my lead screw  has a pitch of 4mm and my stepper motors have 200 steps/ rev, so when the gantry moves 4mm the motor makes 200steps and for 1mm it makes 50steps).

Now will adjust the velocity of the gantry (I set it to 1000mm/min for now) and the acceleration to 50mm/sec/sec.

The last images shows how to configure your hot keys and how to configure your soft limits for each axis.

Step 26: Testing the Mini CNC Machine

And finally the last step, testing the CNC machine.

In this test I used some V shape bits and a cylindrical bit. I am still waiting for some good bits to do some real cutting.

Enjoy.



Here i used a 5mm cylindrical bit.



And here a v shape bit


Step 27: What`s Missing?

What do you think that is missing or what is not very clear at this project?
I wood like to make it better.
If you have some ideas or suggestions please free to tell.
<p>Like very much. Could you reupload all complete files? Thanks</p>
<p>If this is a Mini CNC, the other mini CNC[including mine] are micro CNC :)), anyway, awesome project man, rock-solid build, good work</p>
<p>what the price for all component</p>
Awesome project...<br>I love it!!!
<p>What is the weight of x-axis assembly of CNC in this instructable?</p>
<p>Have you seen a difference in using metal supports as compared to wood?</p>
<p>Hi,</p><p> Is it possible to get the cad file ?</p>
Good job!!!
<p>how many of the parts were bought locally you state &quot;all of the parts were bought locally&quot; i do not know anywhere locally where i can buy lead screws or linear rails or bearings, I am in the process of building a similar model but i have to state that most of the parts are coming direct from china as i can buy them for much less even including shipping compared to buying them in UK.</p><p>do you have any idea of how much in total you spent for the major parts?</p><p>regards Poppy Ann.</p>
<p>Hello. I am trying to find the pdf or dxf files without luck. Can you inform me from where can i found them ??? </p><p>Thank you.</p>
<p>This is Sophia from China and all details can have a look at this website: <a href="http://www.cncrouter.cn" rel="nofollow"> www.cncrouter.cn </a> my mail is sophia@cncrouter.cn </p><p>Any question ,maybe you can ask me </p>
<p>Show!</p>
<p>Awesome instructable. Thanks for sharing it, I'd like to ask you how did you get the G code from a DXF file?</p>
<p>There are programs like CamBam and SheetCam for example.</p>
Looks nice but a true instructable and diy person doesnt order every single component, bearing, rods, couplers etc. We use things from our project boxes, hardware store pieces things like that. We also don't have mills at our exposure for drilling holes. Should have bought one for the money you spent on this thing.
<p>You may be right in your last comment, but I appreciate also the outer appearance and quality of things and am quite sure you can't get anything readymade nearly that money. Have you visited <a href="http://www.worldofcnc.com" rel="nofollow">www.worldofcnc.com</a> (Marchant Dice Ltd)? I think Berbefacac has got plenty of influences from them.</p>
<p>I have for some time planned to build own router, too, and I definitely like your mini CNC router, when I now found the instructable for it. Very thoroughly documented, really. Thanks! The necessary machinings can be done in a local machining workshop. There seems to have been several questions about the accompanying dxf- and pdf-files earlier, too. I have got only four pdf-files through and allthough I can convert them to dxf and draw others myself, the missing ones would save time. There seems to to be no comments from berbefarac for past two years?</p>
Hi. I am having trouble downloading the DXF files from instructables. If I click on the DXF link, I get a 404 error. If I try to right click and download the file, they appear to be empty. Any help please? Thanks. <br>
how called the red electronic board and how much it cost? <br>
Hi berbefarac <br>There is a possiblity to reupload the dxf and pdf files missing from your instructable? <br>Thank you
Super, <br> <br>Va rog, imi puteti trimite si mie planul CNC-ului pe mail. Va multumesc. <br> <br>As fi interesat chiar si de achizitionarea unuia gata construit de dvs. <br> <br> <br>Va multumesc. <br>Dragos <br>dragos900@yahoo.com
Great job! A quick question, though; <br>I'm planning on using 20mm shafting for my machine, too, but I've heard that unsupported shafts can flex quite a bit. Do your shafts have large amounts of flexing, or is it rigid?
What feed rates can you achieve with this?
As I said in step1, the maximum milling speed on X an Y axis is 2400mm/min. and on Z axis is 1800mm/min.
Fantastic machine, very creative and seems to work well. Just on thing, many posts on here ask for complete drawings (dxf/PDF) which you indicate are In sections 13 thru 16, and another post asked whether all drawings could be put in a zip file. This is a great idea, and since I'm keen to also use your fantastic design, could you post a direct link to the drawings or zip file of them? <br> <br>Thanks <br> <br>Simon
Hi. Does anyone have complete set of plans for this?<br><br>Those files are missing:<br>y_cross.pdf (185 KB)<br>shafts_and_threaded_rod.pdf<br><br>All others I already have.<br><br>Thnx<br><br>Kruno<br>
Hi. I will do an update for this instructable and put again the dxf files and all other files needed for the building of the MiniCNC. Hopefuly I will do the update this month.<br>Berbefarac.
Hi, There are still no links to any files showing dimensions at all on the entire page. Could you add the links? Thank You
any news on the plans, am interested in using your design for a project in the uk, especially as your plans are metric. Please put theme up here or send me a link at stefan94@hotmail.co.uk Thanks for supporting the cnc community.
That will be wery nice. Thanx for your time Berbefarac.<br><br>Kruno
Hi. Thanks for this great how-to berbefarac. Anyone got the complete set of plans? My mail is jm_weinberg(at)hotmail.com if anyone can help me. <br>Cheers
Hi, did someone sent you the plans on your email adress? <br> <br>Thnx
No, nobody.
Like some others I attempt to download the plans (in the steps indicated) and get challenged for name and password. I give that and nothing happens. It is as if we are getting trapped in an endless loop. <br> <br>I'd love to see the plans. I'd love to consider making a similar machine but the SITE seems intent to keep us from doing just that. Has anyone downloaded the plans and or found another location that might be posting them?
Having same problem
This looks GREAT ! <br> <br>I'm looking for a reliable DIY CNC machine and this one seems to be a winner. <br>Thank you for sharing this. <br> <br>Although I have one question: how can I download the related files (schematics?). You said earlier <br> <br>&quot;You can find all the drawings in .pdf and .dxf file format in steps 13 to 16.&quot; <br> <br>But really couldn't locate them. I registered on the site (free account) but still no luck :-( <br> <br>Could you please instruct me on how to find those files ? <br> <br>Thanks a lot.
I didn't find the dfx files or plans. Where I can download it?
how much is the overall cost for this<br>
Hey, very very nice work, i was planning to make a some what similar cnc, but mainly just following your z axis &quot;layout&quot;. I was wondering if you think that the structure is strong? Or at least strong enough because I was thinking of adapting a forth and fifth axis to the head and liked how yours for the height advantage. <br>Thanks,<br>Weverton
did you really have to use such big steppers, I mean for a lot less you could have got weaker steppers that are better suited for this task. I dont think you'll ever use their 425 oz. capacity
http://www.youtube.com/watch?v=-5ULOYQ7CuE
First of all, nicely done! As for the stepper sizing, they will only really be oversized if the power supply and driver are not capable of meeting their potential or they are capable of damaging the machine. If all of the electronics are well matched and the machine is free of binding and so forth, larger motors will allow much higher feed speeds to be attained reliably, especially while cutting. Materials that the builder is most likely to intend to mill out with this machine will be able to be be cut at high feed rates.
I would like to try to build a machine based on your design. Do you have DXF drawings of the parts?<br>
Its a great project, but one thing is a bit annoying:<br><br>&quot;For this project you will need to have a set of screwdrivers and a set of hex keys or Allen keys, a drill for some extra holes, metal cutting saw to cut some custom parts, soldering station or soldering gun join the wires so they`ll have a good conductivity , and a multimeter.<br><br>You should have knowledge of basic electronics, how to solder and how to use a multimeter&quot;<br><br>Then later on, it turns out that a lathe and mill are required. Which rather changes things a bit.
Hi.<br>Great work on this.<br><br>Like to build one myself.<br><br>I tried to download plans but there are some things missing:<br><br>Can you send complete plans for Mini CNC router in one zipfile, PLEASE.<br>That would be realy helfull.<br>I have acces to alu-profiles in company where I work.<br><br>Thanx. <br>Kruno
Almost forgot, here is my mail: <br>krunobalaneskovic@yahoo.com<br><br>Thanx.<br><br>Greetings from Slovenia<br><br>
In which step is the dxf file located? Doesn't seem to show up anywhere.
great instuctable... can u help me for software purpose? i,e. how &amp; which soft ware u used. can i get the microcontroler and servo/ stepper motors prog? pls.......<br>
I WANT TO MAKE BUT SOME PRBLEM IN SHOFTERWARE SIDE , CAN U HELP ME ??
How can I help you?

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Bio: I am a mechanical engineer designer, passionate d by CNC machines.
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