Next Gen Printer

I purchased a Trinity Labs Aluminatus One (A1) as part of the discounted "first fifty" offered in December of 2012. At the end of May 2014 Trinity Labs announced that they were going our of business. While there were a number of reasons why that happened, the fact remains that I now need to move beyond the A1. I've managed to incorporate 3D printed parts in my CNC cut designs to the extent that I need a reliable printer 7x24. What I really need is a pair of reasonably identical printers so that one can be running while the other is out of service, either for repairs or upgrades. I've made offers to folks selling used A1's, but I'm not offering a lot and I have not had any takers. I suspect I'll be better off in the long run moving to something else. These pages describe the search, explain my reasoning, and document the choices & suppliers I been looking at.

I'd like to thank Jeff (Jean-François Talbot) for posting his Ike:CoreXY printer design on the TL forum and Thingiverse. It got me started on this project and gave me some fruitful directions.

Budget
I don't have a large budget for this adventure. Indeed, the original A1 was more costly (at $1699) than I was planning to spend. I was following Mike Payton's MendelMax designs but he ran into staging/delivery issues and shutdown his store. Then he merged with TL. Instead of the MendelMax 1.5 design that I was expecting, TL released the A1. Mike eventually left TL and formed MakersToolWorks. MTW released the MendelMax 2.0 but it wasn't available in the December 2012 time frame when I had funds to commit. The steep discount on my first batch A1 was the only reason I was able to afford it. My target for cost of the new printer is in the same, less than $1500 range.

Market
I've researched most of the A1's competitors. I need a printer that can print 14 inch parts. The 12x12 bed of the A1 just manages by turning the parts on a 45 degree angle. That's not optimal and I'd prefer something that can print those parts on axis. Unfortunately, that puts the real products out of my price range. There are a few, as yet undelivered, products that come close, but having experienced an Alpha product release with the A1 I'd rather design my own than live with someone else's problems.

Design Objectives
Here's my 'wish list' that is driving the design. The List may change as I think of things I've forgotten.

ABS printing - implies heated bed (110 deg C) and enclosed printer (no PLA parts)
build envelope - 8 W x 16 L x 10 H - 200mm x 400mm x 250mm (approx driven by heated bed sizes)
print speed - faster than the A1 (may require moving to a Bowden style extruder)
electronics - RAMPS used in the A1 limits max speed. We were promised Smoothie upgrades but that never happened.
Budget - Less than $1500 (yup, I'm cheap. :-) )

CoreXY
Jeff's posting led me to the following list of CoreXY designs and a larger list of CoreXY and H-Bot printer designs.

It turns out that CoreXY is supported in both Marlin and Smoothie software so no extensive software work would be required.

Next Steps
As a consequence of the design process I'm examining just about every design choice. I started by looking at the existing designs
Existing CoreXY and H-Bot Machine Designs talks about what I found and some of the shortcomings I've identified.
To make it easier to focus on a particular aspect of the design process, I've broken the printer into segments and discuss each separately.