Messages

7531

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: July 19, 2010, 09:06:11 AM »

Absolutely right Sam, just mine is not quite so good. 
Thank you for the kind words.

Purely out of interest :- The technique I am using is slightly different from the makerbot and it is called "Selective Laser Sintering" and more details of the process can be found here  http://en.wikipedia.org/wiki/Selective_laser_sintering
The big boys have excellent results with this method but hey I have only just started out so I am excused from making anything too good. 

Tweakie.

7532

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: July 19, 2010, 06:26:44 AM »

This little bike is very different from the others – It is edible, which means that I get to eat anything I make (after it has been photographed). 

Inspired by the Candy Fab project http://candyfab.org/ this 15mm long bike has not been cut-out, it has been laser printed using sugar.
OK this is just my first attempt and it is perhaps not that brilliant, but it is early days yet and many obstacles have still to be overcome - not least, getting sufficient air pressure to keep the vaporized material off my focus lens without blowing everything else away. There are, of course, many other fusible materials with a much smaller grain structure than cane sugar which may well produce much better results so there is a lot of room for experimentation here. (I have just discovered how fine the particles of laser toner are, having just blown a teaspoon full all over my machine table).   

If I can get a grip on this and overcome the obstacles then 3D printing here we come (perhaps). 

Tweakie.

7533

General Mach Discussion / Re: Unipolar stepper motor with ULN2003?

« on: July 18, 2010, 04:54:27 AM »

Correction to above:-

(Some basic maths shows that if you are using a 12 volt power supply you need to put a 24 ohm 6 watt resistor in series with each of the pins 13 to 16). 

Tweakie.

7534

General Mach Discussion / Re: Rough Motion With Mach3

« on: July 17, 2010, 08:31:52 AM »

Mike,

Have you checked the Win XP optimization doc at the bottom of this page - may be something there that you haven't tried already.

http://www.machsupport.com/downloads.php

Tweakie.

7535

General Mach Discussion / Re: Unipolar stepper motor with ULN2003?

« on: July 17, 2010, 07:24:26 AM »

I thought I had already given you the solution :- "You need to current limit the supply to each coil to ensure it doesn't exceed 500mA per driver (series resistors in line with pins 13 - 16). Also you may need to heatsink the ULN2003".

(Some basic maths shows that if you are using a 24 volt power supply you need to put a 24 ohm 6 watt resistor in series with each of the pins 13 to 16). 

Tweakie.

7536

VB and the development of wizards / Re: How to get the current subroutine file name?

« on: July 17, 2010, 04:58:19 AM »

There are people here George - I am the 21st person to look at this who doesn't know the answer. 

Tweakie.

7537

General Mach Discussion / Re: Geckp 540 and Solid State Relay

« on: July 17, 2010, 04:53:20 AM »

David,

Don't know if this is any help but this is the typical SSR configuration.

Tweakie.

7538

FAQs / Re: steppers novato

« on: July 16, 2010, 01:09:30 PM »

Some additional thoughts here.

If your motors get hot during operation (too hot to comfortably keep your hand on) then you will need to fit series resistors to limit the current through the coils but as said earlier I doubt they will be necessary.

Tweakie.

7539

FAQs / Re: steppers novato

« on: July 16, 2010, 01:05:09 PM »

OK if you are going to run your steppers at 5 Volts then no series resistors are necessary.
The power supply needs to be 5 Volt at 14 Amps (15 Amps is the standard rating).

Tweakie.

7540

FAQs / Re: steppers novato

« on: July 16, 2010, 12:24:49 PM »

According to your diagram - you will only have two coils per motor energized at any one time. As each coil is rated at 3.5 Amps max then for 2 stepper motors the power supply needs to be able to supply (4 x 3.5) 14 Amps. (The most common stepper voltage used for small machines seems to be 24 Volts). The formula for calculating the series resistance is given in the driver spec.

Also, as it says in the driver spec, at this current the board is going to get hot so forced air cooling may be necessary.

Tweakie.