They are over constrained but with linear bearings and the way the
rods are mounted, self aligning In other words, the 3/8ths in version
is using the original T-O-M bushings which bind with any misalignment,
but because the rods are located with caps that attach to the side
plates, you simply slide the carriage to each side and then tighten
the cap. The T-O-M locates the rods in the side plated with the laser
cut holes, then the caps just hold the rod in.
Over constraint is not a bad thing, we just deemed it as such in the T-
O-M. You must take things into context. Overconstraint means we know
100% that axis must maintain it's exact travel and not deviate. It can
cause friction when not set up right and in the case of the T-O-M, we
were moving a high mass stage with small motors and no acceleration
firmware. The problem with the T-O-M design is that there is no room
to upgrade the X motor without cutting a slot in the middle acrylic
plate and removing the power supply. Thus, since we couldn't upgrade
the motor, or reduce the mass, and didn't have acceleration firmware,
the concentration was on reducing all friction, and overcontraint
concerns along with the way the rods wer mounted mattered.
Again, you must take things in context, the new design addresses
alignment and assembly issues, uses baller bearing linear assemblyes
which are much, much smoother and lower friction, and the frame size
lets us use larger motors with double the torque of anything you could
fit into the T-O-M. Some of those things aren't obvious from a
pictures or just a causal look at the design, but make a huge
difference and the entire reason why I chose it as the basis to help
others. One key aspect is dual Y belts tied together, By pulling both
ends of the long Y axis, we ensure the force moving the carriage
maintains alignment. This is the key change from a T-O-M, and of
course, the same design the Replicators use (along with most other new
Let me spin it this way. I spent serious money trying to improve the T-
O-M. I tried the Gecko servo drive and huge motors with the middle
plate mod just to make it fit. The hole setup was a pain with multiple
power supplies, all kind of little mods to mount the linear sensors
and tapes. It printed, it was a lot quieter, but I never got the
impression that it was so much better, it should be a mainstream mod.
A lot of work, a lot of cost, and not a lot of benefit. There simply
are so many problems with the T-O-M design, it's not a quick and easy
fix. Everything from the rod mounting, to the motor mounts, to the
belt path has issues.
Again, here is my short list of reasons why I like the new design.
Space for larger motors, even 3 stack motors liek the MK6 for ultra
Larger build area than anything else out (9x9x9 in).
Space for multiple extruders and any mod or tool attachment you can
Dual belts for Y to prevent cocking of the long axis.
The proof is in how well it works, and sorry, I have done a poor job
of demonstrating that to others. Maybe it takes me selling a couple of
frames to key folks to try out for next to nothing. For example, If I
cut a frame for a limited time of $50, you cover shipping too, and
send these out for some people to try out, would that be of interest?
You reuse most parts of the T-O-M. You only need to buy some smoooth
rod (`$30), about 150 M3 x 14 screws and nuts ($12 from Amazon), and I
highly suggest you get the motors from Ultimachine for another $40
Pick up probably 3 extra 40mm cooling fans from Ultimachine while your
at it. You also need belts and pulleys from SDP-SI, but they aren't
that bad. Those who had a Cupcake before have the required pulleys.
Or, for only a few $ more, you could get 8mm rods for the same price,
get 8 linear bearings at $1.75 each making it just a viable to stick
with the original design ( in other words, $14 more for the linear
bearings). I just tried to give the option since it's supposed to be a
T-O-M upgrade. And, the side benefit is that due to the open, dino-
less design, and that attached 40mm cooling fan, The MK6 has never
printed this well with PLA. You could take some of the ideas and apply
them to the T-O-M, but, it's still the same build area, still the same
rattling noises of the design. I don't have anything like that
happening with the new design and I've been slamming it around day and
night at 120mm/s pushing MK6 1.1lb motor. BTW, dual MK7/8s weigh the
same as a single MK6, but just like the T-O-M, the Replicator cannot
use larger 5.5kg/cm motors as they just won't fit, even with mods.
This is where this design shines. It can do everything a Replicator
can do, doesn't have the crappy platform sag from plastic arms, and
most important, doesn't cost you $2,200!!!!!!! I believe it keeps in
the spirit of the original MakerBots, in that we had some very good
parts (gen3, gen4, Mk6), but the frame was our limit. Look at the mods
for the Cupcake and what it could be transformed into. I love my
Cupcake with the 5D shield, the new motors, Aaron's amazing lowrider
and Z rider upgrades transformed it. Many tried to do it with the T-O-
M but none are the magic fix. Sailfish techncially is the magic fix,
but because it helps to mask the physical faults, we are at the limits
of what the T-O-M can be without a new frame. But the new design is
about besting the Replicator series, while helping T-O-M owners who
feel like they are left behind. Further, the Guy with a Cupcake, MK6,
and I 5 D shield is really in the best shape for this upgrade. They
have the pulleys and at least 2 of the belts!! Again, it's thinks like
that that make me feel this might be the best upgrade in a while for
those who invested in the older machines.
On Nov 26, 2:53 am, "dreamer.redeemer" <dreamer.redee...@gmail.com