Messages

7221

General Mach Discussion / Maximise the speed of your steppers ?

« on: March 02, 2011, 10:51:48 AM »

If like me you use steppers then with this simple little device you could possibly double the reliable rapids (G0 moves) on your machine. Obviously it is not intended to offer any improvement to the G1 feedrates because steppers loose torque as speed increases and a reasonable torque is always required for cutting etc.

I recently spent an hour or so reading and re-reading this thread on the zone http://www.cnczone.com/forums/stepper_motors_drives/32284-my_take_stepper_damper-23.html and although convinced I just had to prove it to myself. Guess what, in the trial, it easily doubled the feed rate before my stepper stalled. This device has been patented so it’s only suitable for personal use but it is so easy to make you really just have to try it.

There is no point in going into the details of its operation here because it is fully described on the Zone - it perhaps looks similar to a flywheel but if it doesn’t rattle then it doesn’t work. Physics sometimes reveals itself in strange and mysterious ways.

Tweakie.

7222

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

« on: March 02, 2011, 10:06:52 AM »

Hi Jen,

I have no experience of belt drive so cannot offer any advise here. (Incidentally the Zing will be belt drive and they work OK).

Not sure about cutting with many light passes, I will have to try this and see what happens. From past experience when cutting profiles a second pass had little effect unless you can get the carbon residue out of the bottom of the kerf. The true solution is probably more laser power so it can be vaporised before it has a chance to burn 

Tweakie.

7223

General Mach Discussion / Re: Mill or Router - which is best for this application?

« on: March 02, 2011, 06:55:25 AM »

Hi Jen,

After spouting on about it I thought I had better try some inlay work. 

This is just wood in wood but it shows that it is easy to do with Mach3 and LazyCam.  http://www.machsupport.com/forum/index.php/topic,12444.msg121416.html#msg121416

Tweakie.

7224

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

« on: March 02, 2011, 06:25:41 AM »

Something I have not really tried before is the inlay of wood into wood. Thanks to Switcher http://vectorink.com/ I downloaded one of his .dxf’s and using LazyCam created the wood cut outline GCode. This was then used to cut some parts from 2mm Obechi veneer. The .dxf outline was then filled black, using Photochop and saved as a .bmp which was subsequently then used with the Engraving / Laser plugin to cut the pocket into a leftover piece of Teak. Both the Obechi and Teak were covered in paper Transfer Tape (the stuff used for applying vinyl signs) before being attacked with the laser to protect the surface from smoke marking and discoloration. The part was then fitted in place using PVA and sanded flush when dry (the part was about 0.5mm proud of the surface).
It is not perfect but hey this is my first attempt, I have learnt a lot here and I am sure that I can make improvements. The edges of the cut have suffered from blackening and unfortunately, this is quite noticeable – perhaps using Nitrogen instead of Air as the assist gas would reduce this effect, something to try another day.

Tweakie.

7225

General Mach Discussion / Re: Mill or Router - which is best for this application?

« on: March 01, 2011, 07:44:52 AM »

 

Tweakie.

btw. The 600W Rofin Fiber laser costs just a little over the price I paid for my house 

7226

General Mach Discussion / Re: Need help with basic understanding

« on: March 01, 2011, 06:32:22 AM »

I have used Draftsight to create DXF files but on occasion I like to use plotter files. I cannot create the plot files directly in this program so I was trying to find a plotter driver that I could print to file. The ones that were recommended to me were the drivers for HP 7475a or HP 7580a. The problem is the HP download site does not have these drivers anymore and I cannot seem to locate them. In addition, I read somewhere that they are not supported on Win XP. So, question is what plotter driver is available and where can I download it ?

Thanks

Perhap WinLine may be suitable for your needs http://www.winline.com/


Tweakie.

7227

General Mach Discussion / Re: My "Bat Desk" is almost done!!!! :) :) :)

« on: March 01, 2011, 02:31:04 AM »

Very impressive Scott but does it dispense Beer ? 

Tweakie.

7228

General Mach Discussion / Re: Mill or Router - which is best for this application?

« on: March 01, 2011, 02:01:38 AM »

No worries Dave 

I think we would all appreciate it if you use the caps lock key though.
Thanks,

Tweakie.

7229

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

« on: February 28, 2011, 12:26:57 PM »

I have received a couple of emails from others who have cut this lizard but said that the parts are too big to fit together properly and asked me how I did it.

Well…..

Eschers original drawing had just one line defining the boundary between each lizard and it’s mate and if you pick one image, convert it to dxf and then cut on the outside of the line the resulting pieces will not fit. Cutting on the centre of the line results in the clearance between one lizard and it’s mate being the diameter of the laser beam (0.05mm). Although it may well now fit (if it was drawn accurately enough in the first place) this clearance is still not enough to enable easy assembly and disassembly of the pattern so this is why I chose to cut on the inside of the line and why I cut the parts separately and not nested.

Hope this answers some questions.

Tweakie.

7230

General Mach Discussion / Re: Mill or Router - which is best for this application?

« on: February 28, 2011, 11:30:50 AM »

Jen,

You are right about wood's density. Wood's like teak and spruce have a soft growth layer sandwiched between a very hard annual ring - the laser will cut deep into the soft and not so deep into the hard but the overall average should be pretty constant.
As the depth of cut is related to both power and speed as well as the wood itself the exact depth will always be a trial and error thing but once established it will be repeatable, at least for that sample of wood.
There will be some blackening (charring) around the edges but the surface of the work can be protected with paper transfer tape (used with vinyl signs) also there are a number of  proprietary cleaners which, I understand, can work wonders.

(Incidentally, the smallest practical beam spot size is around 0.05mm diameter without resorting to beam expanders or extremely short focal length lenses).

Tweakie.