Parts/sources to buy RAMPS/general RAMPS questions

Ello all.

I've decided that since it'll be may before mendel-parts will have any more gen6 electronics, pololu RAMPS seemed to be the best option.

But I'm having a lot of difficulty finding a distributer. ultimachine.com is out of stock, and the only other place I can seem to find is reprapsource. But even then, the most complete kit they have is in pieces and needs to be soldered together, and I'd need to buy the stepper drivers and arduino mega separately. The soldering isn't a problem, it's that I have about a month to get the electronics and have it running.

Are there any other sources I can check? Am I right in that all I need is an arduino mega, the pololu shield and the stepper drivers to be ready to print?

You also need 3 opto-endstops: [ultimachine.com]
You should send email to Ultimachine, normally they put it back in stock quite fast.

Are the gen 3 endstops (Techzone Gen 3 remix) compatible with RAMPS? The seem to be pin-compatible.

I was just about to ask the same thing, ultimachine seems to just have mechanical ones in their kit.

Which gen 3 endstops? Those one http://reprap.org/wiki/Generation_3_Electronics/Tech_Zone_Remix/How_to#The_Opto_End-stop?

If you are talking about the previous one, they are just opto-sensors... For the ramps you just need to add some resitors to those opto-sensors....

Call ultimachine, they just received a complete set on Tuesday that had been lost in the mail to me for the last two months, they may still have it in stock. Also they do have both opto and mechanical endtops even if the web site does not say it. JUST CALL

I recommend mechanical endstops. [www.redwizard3d.com] has them, or you can make your own with the microswitches from reprapsource. They work better than the optos for me (not sensitive to sunlight).

Kliment

Really? I had no idea that opto endstops were sensitive to sunlight.

Though, the more I look into this, the more I'm considering building the gen7 electronics. Seems like it'd be cheaper and more DIY... still undecided though. Thanks for the help everyone.

It's true, optical endstops will be less reliable than mechanical ones, opto ones maybe a little bit more sensitive but will need to be enclosed for the best part to stop dust, stray light, etc. Ultimachine supply good mechanical ones in their kit, I used a belt splitter part from a standard mendel platic set to mount on my z-stage bar, two M3 bolts and nuts with washers provide a decent mounting option on one of the the z bars, but i will replace them with printed parts for the job. I'll get a pic to demonstrate the parts used on the morrow. I used larger roller maplin ones on my x and y stages as they don't need to be so good (keeping the Ultimachine ones for later machines).- It maybe that larger more robust ones are better to install as well.

It's only the min z stage you need sub-millimeter repeatable activation on as everything else should be relative. My initial print startups have generally failed due to head height alignment to the bed, so superfine positioning is required for the endstop is needed.

Mechanical switches wear out with each use while optical switches don't. The optoswitches operate in the IR at 950 nm so there's not as much sunlight there. So, I don't know if it will still work in sunlight. Has anyone checked? The thing I don't like about the optoswitches in the Mendel is that it's easy to knock the flags or the switches out of alignment. In the x and y, it's not that big a deal. But in the z axis, it can cause some serious damage.

Micro switches will last for tens of millions of operations when operating at low currents. Since they are only needed once per build that means they will outlast the owner of the machine!

There is plenty of IR in sunlight and it will affect optos if it shines directly on them. The flag needs to be both opaque and non reflective at IR.

Given the amount of trouble people have with optos I think micro switches are a much better option for this application as long as you don't home every layer like Adrian does.

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