CNC Stuff

Posted by admin on October 30, 2011

CAM Software Options:

  1. HeeksCAD/CAM - Free, and there's a linux version.
  2. DeskProto - Seems great for proto stuff.  Not too expensive either.
  3. Vectric - Offers several different CAM packages from 2D to 3D.  Cut 2D is interesting for the mill.

CNC Controller:

  1. Mach3 - Works and very popular, but I find the interface to be terrible.  Also has issues with running on a laptop, which I have addressed and resolved here.
  2. EMC2 - Linux based CNC controller.  Supposedly has superior parallel port communications.

 

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Using Mach3 on a Laptop Parallel Port

Posted by admin on October 28, 2011

Mach3 uses the Parallel Port to communicate directly with a CNC motor controller board.  This requires that the software be able to take full speed control of the parallel port.  If there are any delays, steps or other info will be missed.

Laptops have a lot of power management controls that can slow down communication over the parallel port.  Here are the steps that worked for me to be able to run Mach3 on a laptop.  In the end, the main problem appeared to be the processor wanting to sleep all the time, so the key was a program which kept the processor active and running at full speed all the time.

  1. Turn off all power management in the Bios
  2. Remove all unnecessary background processes in windows.
  3. Install RightMark CPU Clock Utility (RMClock) - Download Page - Direct Link to Download File.
    1. Download and install the CPU RightMark from http://cpu.rightmark.org/2.
    2. On the profiles screen from RightMark for "AC power profile" select "MaxPerformance”.
    3. Check the "Run HLT command when OS is idle” , uncheck the "Use OS load  based management,” and click apply. It will ask for restart and click ok to restart. It will not restart the computer, only the RightMark CPU application.
  4. SUCCESS!

RightMark CPU Clock Utility was the critical component that got it working perfectly.  It's possible that it's the only thing that you need to do, but I had already performed the previous steps.

 

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Laser Cutter Water Cooling System and Cart

Posted by admin on October 26, 2011

Water Cooling System:

The 40W CO2 laser tube being used for this laser is water cooled.  Using surplus parts we already had, we went a little overboard with the water cooling system.  It uses a radiator from an industrial dehumidifier, and a water pump from a surplus contact lens assembly line machine.  A reservoir is custom built from a piece of 4 inch PVC pipe, and uses a flow switch as feedback.

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Most inline red laser pointers require an extra mirror that is transparent to the CO2 laser wavelength, but reflects the red laser beam.  The mirror is setup at 45 degrees to the path of the C02 laser beam. I don't really have much space to easily mount that, nor do I want to buy more mirrors and mounts.  This device allows for an inline red laser pointer, without adding an extra mirror to the setup. The red laser drops down into the laser path when the door is opened (and the laser is off). It is designed for the Buildlog.net 2.x laser, but can be adapted to other designs.

It was made on my UP! 3D printer. If you don't have a 3D printer, let me know and you can buy a set from me.  Here are the files if you would like to print it out on your printer:

DOWNLOAD: 111023 inline red laser pointer STL files

 

CAD showing the door closed and laser in the up position.  The door closed (laser interrupt) switch is by the lever part, not by the door.  So the red laser has to be up and out of the way of the main laser beam in order to close the switch.

 

CAD showing the door open and the laser in the down position.  Now the laser is inline with the normal beam, and will create a red alignment dot on the part to be lasered.

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Laser Tube and Mirrors Alignment Device

Posted by admin on October 23, 2011

The laser tube mounts and mirrors must be aligned before the laser can be used. It's kind of difficult when the laser you're using is invisble and can burn something within a millisecond.  I designed and made a mount for a red laser pointer to be used to help in aligning everything before inserting the laser tube.  It is also useful for test running the whole machine prior to laser install.

The files can be downloaded here:

Laser Tube & Mirrors Alignment fixture Solidworks and STL Files

The way this works is that the piece to the left goes closest to the exit of the laser tube, and the piece to the right holds the red laser at the opposite laser mount, close to the rear of the tube.  The left piece has a pinhole in the center.  The laser must be aligned to shine through the pinhole.  This assures that the beam is properly aligned down the center of the laser mounts.  Then the mirrors can be aligned. Once everything is set, one screw on each laser mount is unscrewed, the alignment tools removed, the laser tube inserted, and the screw retightened.  Everything should be properly aligned at that point.

NOTE:  The left print looks thin in the center, because it missed a few layers due to my error while swapping filament mid print.  The machine print's beautiful... I'm the one that messes up.

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Sherline Mill (Milling Machine)

Posted by admin on October 10, 2011

Click here to view a Tear Down of the Sherline Mill at the Take Aparts website.

ER16 Collet System

I've read that the ER16 collet system is ideal for the size range of these milling machines. I believe some of the Taig machines come standard with the ER16 Collet Chuck.

ER16 Collet Chuck

The Sherline has a #1 Morse Taper (MT1 or 1MT) in the spindle head. Thanks to Ebay, you can finde MT1 ER16 Collet Chucks.  The other option is a 3/4-16 thread ER16 Collet chuck. The MT1 is probably better for proper alignment.  The 3/4-16 thread chuck might be good for the lathe, because you can pass material through the chuck.

The following chuck was found on Ebay for ~ $25 shipped.  The runout is speced as 0.0005, which is not as good as high end chucks, but should be good enough for this use.  Search "MT1 ER16" in order to find it.

UPDATE: I received it, and tested it out in the Lathe.  Works great, and runout on the inner surface of the chuck was less than 0.0005.  With the collet, runout was 0.0005 while holding a precision ground shaft. The collet nut did have a bur around the entrance that I had to sand down to improve the run out.  Other than that, the quality seems quite good.

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Prazi MD65 (SD300) Lathe

Posted by admin on October 7, 2011

Click here to view a Tear Down of the Prazi Lathe at the Take Aparts website.

Made an incredible find on Craigslist.  A Prazi MD65 (SD300) lathe and BFE65 milling head brand new in the box, straight from East Germany in 1988!

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Prazi MD65 (SD300) Lathe

Posted by admin on October 7, 2011

Click here to view a Tear Down of the Prazi Lathe at the Take Aparts website.

Made an incredible find on Craigslist.  A Prazi MD65 (SD300) lathe and BFE65 milling head brand new in the box, straight from East Germany in 1988!

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Laser Cutter Skins and Air Filter Installed

Posted by admin on October 5, 2011

The side and bottom panels are cut from 1/8inch HDPE. This material is inexpensive, easy to cut, and durable. The pieces I ordered from McMaster already came close to the correct size, so there was minimal cutting required. The top is Grey Tinted Polycarbonate, because I wanted the coolness going on inside to be visible. It's not as dark as I was hoping for.

An air filter is installed on the right side. Clean air is pulled in over the electronics. Hopefully this will reduce the amount of dust in the unit. The air filter is a standard 10"x20"x1" home air filter purchased from Home Depot.

I'm considering mounting the exhaust to the underside of the Z table. This way it can be used as a suction table also to hold flexible stuff flat.

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Sherline Lathe

Posted by admin on October 3, 2011

I purchased a used Sherline 4000 Lathe on craigslist for $140.  It was in excellent shape, but had no accessories included.  Using the Sherline History page, I was able to identify the lathe as being made in approximately 1990.  It has the 1/2 hp AC/DC (Universal) Motor.

Drive Motor and Speed Controller

There are a few options I've investigated for a new drive motor and controller.  The current motor has a nice amount of power, but the speed controller does not hold the speed very well, and pulses at low speeds.  The current speed controller is just a basic AC motor controller, but the motor is AC/DC brush type motor.

Use the current motor and replace the speed controller.

Since the motor is an AC/DC 115V motor, a DC speed controller can be used to run the motor. Any 1/2 horsepower, 115V AC input to ~90V-120V DC output controller should work fine.  KB electronics is a commonly used brand for newer mini lathes.

SCR Speed Controller - control speed using a potentiometer, less expensive KBIC-120

PWM Speed Controller - control using a pot, analog input, or PWM.  Speed can be controlled from CNC software. KBWD-13, or KBWD-16

Stepper Motor.

A large stepper motor could provide fine speed control, and be easily controllable from a CNC controller.  Maybe this could be used for threading?

Stepper should be about 5-6 Amps.  Gecko G723-400- $59.00

Controller: Gecko G210X  $140.00

Replace motor and speed controller with a DC motor.

Expensive, and off the shelf setups don't have the ability to be CNC controlled

CNC Control

CNC control can be useful in more ways than just automation, or making difficult shapes. Threading can be done using CNC instead of the complex threading setup using change gears. By adding an encoder to the spindle pulley, the CNC system can keep track of the spindle position, and drive the carriage to cut the correct pitch thread. The spindle will be turned by hand for most threading operations, and the carriage will follow, being driven by a stepper motor.

Sherline sells a stepper motor adapter for the axis of the lathe and mill. It's part number "Sherline 67102", but I can't find it for sale anywhere, and I suspect that it's pricey, like all other sherline accessories. A2Z CNC is the only vendor I found that sells an adapter. Item Code: CNCMMS

To convert a single axis to CNC, you need the following:

  1. A2Z CNC Nema 23 motor mount for Sherline Mill & Lathe - Item Code: CNCMMS $49.95
  2. Sherline CNC Motor Coupler - Item Code: 67105 - 15.95 
  3.  5-40 x 7/8" Socket Head Cap Screw - Item Code: 67115
  4. Nema 23 Stepper Motor with ~200 oz-in of torque.  The Gecko G723-280-4 maybe overkill for this application at 280 .oz-in of torque but $59 is reasonable for US made motor.

The controller will primarly be an Arduino microcontroller.  This standalone controller will be perfect for setting feedrates and thread pitches.  Optionally the motor drivers can be connected to the computer for full CNC control.


 

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