I fixed the gaps between the perimeter and infill by adjusting the extruder multiplier. However, when I print a single wall partas per the flow rate tutorial (http://wiki.solidoodle.com/flow-rate), I no longer get accurate wall thickness. Anyway, at least the perimeter is no longer separating from the infill.

Thank you for your help

1) Speed was fine. All settings were fine except for Seem Position: Aligned. The messy corner we were seeing is the "Aligned" seam position. I changed this option few days ago and that's when the messy corner appeared. I changed it back to Random.

2) I re-leveled the bed. That improved the print quality dramatically! It was off by just a tiny bit but that can make a very messy start which affects all the other layers! Right now the distance between the nozzle and bed is 0.25mm (I used a feeler gauge).

3) I printed "limits" for the Y rod (see attached image). I am not sure if it's a good idea or not, but so far it's working great! I hated how the Y rod kept moving side to side. I printed a "limit" for both ends, and the limit is adjustable with a screw. I used plastic screws because I didn't know if I used metal screws if they will make a noise; I attached the limits to the printer's body with a double sided tape and it's holding great so far (screws are always an option). I gave it just enough space (1mm in total) for it to rotate freely but not to move from side to side too much. Like I said, so far they are definitely not interfering with the movement of the Y axis. And my last print was much much better!

4) I thought I got rid of the gap between the infill and the perimeter by turning on the "Infill before perimeter" option--while printing the infill looked spot on and no gaps, but after the print was finished and everything looked nice I checked the part and the perimeter separated from the infill (see green lines in attached image of where the wall were separated from the infill after the print).

Thank you guys very VERY much! You are the best! If I can only figure out the separation of the perimeter from the infill, I would be happy with the print quality.

not sure how much of a difference there was between the SD3 and the SD4, but I was getting good results from ABS at about 195-200C on the stock hotend, and 100C bed.

definitely want to check those speed settings, too - it does look like it is running a bit too fast.

I did print it with support material. This image is of the part after I removed the support material.

Last night I tried to print something else and it came out pretty decent! I am happy! At least the part resembles the 3D model

Two concerns though:

1) There seems to be this weird "extra" material at the edges (sorry if the description doesn't makes sense, see the attached image.)

2) Two cut outs have tapered walls instead they came out almost straight.

Any ideas? (First point is more important than the second one, I can change the dimensions of the cutouts for the second point, but it would be nice to figure out the first problem.)

Thank you very much!

They came on the market on the tails of maker bot. They were attempting to make an affordable durable  home 3d printer.  The first makerbots and ultimakers were laser cut wood frames the sd frame is metal. Itis easy to look back and see where they faled but lets just build on the success.

I have 2 of the SD4s - both of which were purchased used. A few upgrades/modifications, and a bit of tweaking and both are incredibly reliable machines now - and quite accurate, too.

From where I sit, you get out of them what you put into them. Take the time to set them up RIGHT (and yes, this means "fixing" the poorly implemented parts) and you can have a very good, reliable printer.

My #1 SD4 - after modding/fixing what needed fixing - has been run for 10-12 hours a day, 7 days a week at times, with pretty much no downtime. I rarely even need to touch the bed leveling anymore (and No, I do NOT use any kind of "auto-level" system - on either of them).
What has gotten these machines to this point of reliability is learning what I needed to learn, fixing what I needed to fix, and upgrading what needed upgrading.

Did it happen overnight? No. It took several months of learning with the first one. The 2nd one was much easier because the learning curve was flattened out by then, but even that one gave me moments of WTF?

I don't care what any company claims - there is NO "plug and play" 3d printer on the market that costs less than $1000. I would be willing to bet that even at the $1500-2000 price point, there are going to be issues to be dealt with.

And even the best 3d printer on the market STILL requires you to learn the software needed to run it, which, in and of itself, can be a challenge.

Just as with any kind of tool - you MUST learn how to use it right.

I heard the CR10 is amazing and affordable. I am in Toronto, Canada so I had to pay CAD$1,000 for the SD3 (including shipping and taxes), so it's very frustrating and disappointing to deal with so many problems for such a high price.

Anyway, I don't hate the SD3, I think it can be decent. I got to work on it.

If you need a 3d printer for your work  you may want to try something like a wanhoa https://www.amazon.com/Wanhao-Duplicato … B01CGB8LA6

But i suggest you get what you have working before you try a different printer.
Like i said earlier welcome to the world of desk top printing . There is a bit of a learning curve.
Dont hold it against simplify 3d every printer and filament will need different settings .
This is a case of    wishing i knew your location.
I have a friend that does classes on  3d printers . 

https://printedsolid.com/collections/3d … electclass

https://printedsolid.com/collections/3d … g-your-own

So if you are anywhere near Delaware this could be a fantastic opportunity to learn.

Thank you for your encouraging words. I agree with all!

The thing is that I am not a fan of 3D printers. I am a design engineer. The printer to me is just a tool. It's cheaper and more versatile than injection molding, casting, CNC maching, sheetmetal bending, etc. So to me the SD3 is just getting in the way of seeing my designs in real life; the opposite of why I purchased it!

The other thing that's frustrating me is that the SD3 was poorly designed and made (sorry to say this: but I don't feel bad for the company for going bankrupt!) It's hard to tweek something with such bad design elements, e.g.: tensions the Y axis by going back and forth and back and forth until the Y rod stays in the middle!

It's like the creators of this 3D printer didn't sit down and plan it. Just like the creator of Simplify3D: I purchased the software, installed it, choose SD3, and it was worse than Slic3r. Why would I pay $150 for a software and choose my 3D printer if I still have to go into the settings and change them; I might as well use the free Slic3r software!

Sorry for ranting, but I am just tired of poorly made products.

And I took your advice: I am back to trying to figure out what's wrong so I can get it working again.