Rack & Pinion with Retina Controller

Bearings/Motors/Belts/Gears/Etc.

Re: Rack & Pinion with Retina Controller

Postby r691175002 » Tue Dec 28, 2010 9:20 pm

macona wrote:Oh, supposedly you can modify the steps per inch setting in the parameter XML for the RetinaEngrave.

I would be cautious when using non-integer steps per inch. The retina was never designed to be easy to integrate with a diy machine and I wouldn't be surprised if weird things started happening with 1000.772 as a parameter.

I'm also planning a machine using the retina controller (abeilt just the small buildlog.net one) and I think belts might be the way to go. I was suspicious of their positioning accuracy but apparently the guys at cnczone regularly use belts on 8x4' routers and can make 0.001" no problem so they must be pretty accurate.

The DSP controller from LightObject does the same stuff except instead of a universal print driver (The retina can cut from any program very easily and do combined raster/vector cuts) you are stuck with only an outdated correldraw and autocad plugin (both plugins are for older versions of the software). I am a little hesitant to commit to a controller that is forever locked to outdated software when the retina is still being updated regularly.
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Re: Rack & Pinion with Retina Controller

Postby lasersafe1 » Wed Dec 29, 2010 3:26 am

r691175002 wrote:The DSP controller from LightObject does the same stuff except instead of a universal print driver (The retina can cut from any program very easily and do combined raster/vector cuts) you are stuck with only an outdated correldraw and autocad plugin (both plugins are for older versions of the software). I am a little hesitant to commit to a controller that is forever locked to outdated software when the retina is still being updated regularly.


The LightObject dsp also has its own operating software that does not rely on CorelDraw or AutoCad. As far as your comment about outdated..., Well, the software still runs fine in Vista. I haven't changed to Windows 7 and I doubt that I will for my workshop PC. The older software can do anything we need it to do for this type of work and it can often be obtained free of charge if you know where to look. Believe me, I'm not forking out $2500 for software just to run my laser.

It is not unusual to have to deal with older versions of software. I recently designed an overlay with tactile switches using CorelDraw X4. When I sent it to the manufacturer, they wanted it in version 11 because Corel stopped supporting Mac in version 11. Since graphic artists love their Mac's, they are stuck with the last version that existed.
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Re: Rack & Pinion with Retina Controller

Postby PSG » Wed Dec 29, 2010 12:52 pm

Thank you all for the responses :)

The reason I am wanting to use the Retina is because of its apparent and reviewed engraving capabilities. The software side of things is of a value but the cost of constantly updating software can be prohibitive, and that takes a back seat. By the time software becomes an issue, there is a new piece of hardware.

The concerns with the Retina are:

1) As stated on their own website, no support for the DIY. It is understandable, considering the developers have "other" responsibilities, but that equates to making sure that all homework is done PRIOR to making the leap. Otherwise, you can end up with and expensive piece of useless hardware.

2) "1000 steps per inch". I like the R&P setup, especially on the X. On my router it saved me lots of $$$ over a quality screw. With a rack, though, I have not been able to figure out a combination to get an even 1000 s/i. I am assuming that it is because of the value of pi. Everything considered, will ".772 " make a real-world difference? Will the Retina go haywire?

I think I can compensate for the slight difference in part size. I am not sure that it will matter that much for what I do anyway - I deal with "nominal sizes".

3) I completely understand the resolution of the "artwork" on the Retina. Is the 1000 step requirement solely for the artwork or is it for the "operation" of the machine? I fully understand Mach and can deal with all of that.

With all of that said, I did locate belts that I feel can handle the distance of 8 feet. I have pitch choices of .200" (1/2" width), .375" (3/4" width) and .500" (widths 3/4" on up). The .500" calculates to a toothed pulley of 4 (I think), meaning that I think would be looking at a 16 tooth pulley with a reduction of 4:1. Building the reduction units are not a problem (my friend is one of the best fabbers I know) but going from a .250" shaft on a NEMA 23 to ultimately a .625" shaft for the final drive pulley just seems like a PITA, as requiring 3 (possibly 4) pulleys. Maybe just familiarity but the R&P just seems so much easier to implement on the larger machines (although belts seem like the smarter and easier choice for the smaller units).

Is there any way I can get some input from the makers of the Retina?
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Re: Rack & Pinion with Retina Controller

Postby fullspeceng » Fri Dec 31, 2010 4:53 pm

We can support any resolution in vector mode.

In raster mode, there's simply no mathematical way to correctly to scale a bitmap image when they are not integer multiples.

All your data will look stretched out but that's the only problem without using different resolutions.

Sure we could just rescale the image using something like bilinear interpolation but that output isn't bit perfect. This is also the reason our software does 250, 500 and 1000dpi and not 750dpi or 300 dpi, etc.

We are experts in image processing and know when something is just not a good idea.

We have already recommended a specific set of pulleys, belts and stepper drivers that give 1000dpi and we recommend you just stick with that without modification.
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Re: Rack & Pinion with Retina Controller

Postby PSG » Sat Jan 01, 2011 2:33 am

Thank you for responding. I tried registering on your store but could not get past the verification...way too hard to read.

Anyhow, I too do a lot of image processing, so I understand what you are saying. I did not understand that we were outputting to a rip. Now it makes sense.

Looking around the fse site, I did not see the recommended combination. I will look again but is it possible to get a link and would that recommended combo work on a 4x8 machine?
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