FabMiller 4230 (WIP)

fabmiller

 

 

HOW TO BUILD A HOME MADE CNC MILLER

 

FABMILLER 4230

 

 

1. Inventory          2. Mechanics          3.Electronics


 

FabLab EDP presents to you its newer project: a low cost CNC Miller, FabLab 4230.

This CNC Miller was built to help everybody that’s out there and needs a CNC but can’t afford a commercial one. This is our attempt to help you to build your own low cost CNC.

 

 

Dimensions: 1x0,7x0,5 [m] (length x depth x height)

Weight: 20kg (approximate)

Working area: 420x300 [mm] – A3 SHEET

Material: Valchromat (Red)

Version 1.0

Project development duration: 3months

Real building time: 1 week (working as hell!)

 

Before Building it…

 

There are some expertise you’ll need to develop before building this machine:

  • Milling (in order to cut the body pieces)
  • PCB building (including milling the board and welding te components)
  • Using arduino with GRBL
  • Laser Cutting

 

I advise to you visit this fabacademy page and visit the tutorials related to the topics that you don’t know or don’t master.

 


Inventory


 

When building this machine our main gold was to keep it cheap without putting quality at sake.

 

Here in Portugal we had a huge difficulty to find the building components in Portuguese stores. Luckily we found almost all the solutions at Leds and Chips (Lisbon).

 

The inventory is divided in mechanics and electronics because they need different concerns when bought.

 

            Mechanics

 

The mechanics involve all the materials used to build the CNC Body and putting all parts moving.

 

Body

The body was built using 16mm thick Valchromat (you can learn more about it at http://www.valchromat.pt/ ).

We chose this material because it’s easily milled and is an exclusive portuguese product. However, if you really want to keep it low cost you can use regular MDF that, for the same board size, costs €15 (instead of €106).

 

Lead Screws

Since this CNC Miller is kinda big for a “home made” we needed to use thicker lead screws than usual. In the beginning of our project we used lead screws with 8mm diameter but the screw path was too small and the machine was too slow. This lead screws offer a bigger path which allows us to obtain faster movements of the axis.

           

Shafts

You’ll see that we used 8mm shafts to guide the axis instead of linear rails because they were more versatile in an iterative process. If you wish you can choose linear rails. The drawings are ready for 8mm shafts. Tubes where not able to hold our structure so we (really) don’t advise you to use them.

Spindle

We wanted as much as power as we could get in order to cut a bigger variety of materials so we chose a 400W DC Spindle – the bigger that inventables had. A 400W DC motor controller needed huge electronics and it was cheaper to buy an already made controller than to produce one.

         

 

Bearings

In order to have an easy maintenance machine, we chose bearings that you can find everywhere because they are also used in PRUSA 3D printers. By choosing this bearings we know that our local fablab supplier will have them anytime.

 

 

Description

Quantity

Un. Price (€)

Subtotal (€)

Seller

Evaluation

Nema 17  42BYGHW811 Stepper Motor 3,1V  2.5A

3

 €             15,00

 €              45,00

Leds & Chips

*****

M8 Motor Coupling

3

 €               6,75

 €              20,25

Leds & Chips

*****

M8 Bearing 608zz

3

 €               0,65

 €                 1,95

Leds & Chips

*****

LM8UU Linear Ball Bearing

12

 €               2,00

 €              24,00

Leds & Chips

*****

400W DC Spindle

1

 €             94,26

 €              94,26

Inventables

****

DC Spindle Mouting Block

1

 €             23,77

 €              23,77

Inventables

****

ER 11-A Collets

1

 €               5,93

 €                 5,93

Inventables

****

ER11 Collet Nut

1

 €               5,20

 €                 5,20

Inventables

****

ER 11  Collet Wrenches

1

 €               4,46

 €                 4,46

Inventables

****

M12 Nut

6

 €             10,00

 €              60,00

local seller

***

M12 lead screws (3 sizes)

1

 €             80,00

 €              80,00

local seller

***

Valchromat 2000x1850x16 mm

1

 €          106,00

 €            106,00

Banema

****

Screws and Nuts M3x20

1

 €               1,99

 €                 1,99

Leroy Merlin

****

Screws and Nuts M3X30

1

 €               1,99

 €                 1,99

Leroy Merlin

****

PVC Boards

3

 €               5,50

 €              16,50

Plexicril

****

stainless steel shaft 8mm - 240mm

2

 €             12,00

 €              24,00

Leds & Chips

*****

stainless steel shaft 8mm - 575 mm

2

 €             15,00

 €              30,00

Leds & Chips

*****

stainless steel shaft 8mm - 970 mm

2

 €             20,00

 €              40,00

Leds & Chips

*****

Spindle Speed Controler

1

 €             24,00

 €              24,00

Leds & Chips (through Ebay)

*****

     

 €            609,30

   

 


 

Building it…

 

Mechanics   

 

So the basic steps to create this CNC miller are design it, cut the material and mount all the pieces like a puzzle.

Luckily for you the design is already made.

In our CNC we used a 3mm driller (as you will realize in the drawings there are 3mm gaps and circles) and took us more a less 8 hours to mill every single piece.

In our machine we also cut a few pieces using laser and printed 4 supports for the PCB.

 

Cutting

Our CNC got a little crazy when sending all the pieces, so we advise you to cut the pieces in little groups.

 

We also set different layers in order to make the path selection faster:

  • Outside
  • Inside
  • Pocket 3mm
  • Pocket 10mm

Be aware that in some pieces you won’t see the dog boned corners. That’s because we realize that the CNC “didn’t like” those so we inserted them in the Aspire. When exporting the drawing to DXF pay attention to the setting, we used “2004 Natural”. Other settings exported the circles as a union of several points which had a huge size of information and the CNC got crazy with it.

We also set the drill’s velocity at 50%. Drill cut depth 1,5mm. The tabs were 2mm long and 2mm thick.

After cutting and before mounting we advise you to remove tabs and get the surfaces really nice and smooth.

 

 

Mouting

First sort all the pieces and place them by the groups that we suggested.

We advise you to use this mounting steps:

1.       Mount the axis boxes

 

2.       Insert in this boxes the bearings and the 12mm nuts (the big ones for the lead screws) – we used hot glue to hold the bearings in their place.

 

 

3.       Using the M3X30 screws place the nuts fasteners between both nuts surfaces and fasten those. By the end of this step the nut shouldn’t move what so ever.

 

 

4.       Screw the lead screws in all the axis boxes.

5.       Fasten the motor coupler in the lead screws shaft area

6.       Place the spindle in it’s mounting block

7.       Place the spindle mounting block in z axis box and fasten it with 4 M3X30 screws and M3 nuts.

8.       Mount the pillars A and B together in the back wall (2x)

9.       Place the new pillars in the base.

10.   Place the top on the pillars.

11.   Mount the x axis support 1 and place it on the base

12.   Mount the x axis support 2 and place it on the base

13.   Screw the Nema 17 motors in which axis

a.       On axis x, in the support 3

b.      On axis y, in the right pillar

c.       On axis z in the y axis box top

 

14.   Mount the x axis support 3 and place it on the base.

 

15.   Place the x axis bed between supports 1 and 2

16.   Screw the coupler in order to fixate the motors shaft

17.   Insert the 970mm shafts in both places, right know your x axis should be perfectly mounted

18.   Place the z axis box inside the y axis box and insert the 240mm shafts throw y axis top 8mm holes.

19.   Screw the coupler with the z axis motor shaft.

20.   Place the y axis box in the place using the 575mm shafts

21.   Screw the coupler with the y axis motor shafts.

 

Congrats!You have all the mechanics mounted. Place all the wires in the right pillar.

 


PROJECT PHOTO REPORT


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Last updated: 09/10/2015