WOW! That IS amazing. The way it just tears the foam into useful stuff, I'm stunned! And just this monday I was thrilled about my phlatprinter after installing a new Y-stepper and increasing speed to about 34 ipm. I was happy with that and now you spoiled it Mark Fortunately, I have planned a major surgery of my printer because I want to extend the Y-axis to about 800mm instead of 600mm that is standard, so I will have a great oportunity to incorporate the MKII drive system.

Thanks Mark and Trish for what you are doing for the CNC/RC community!
/Jan

 

Yes, I'm really glad that the Y-axis has been stretched on the MarkII. I'm bumping into the stops on mine trying to get that last millimeter of foam used.
Dave

 

The latest vids of the Mk2 look great, nice work M&T!

I'd like to know how the cut quality compares between foam cut at 30ipm and 300ipm. I can believe that the accuracy is just as good, but i've found that I get better quality results at slower speeds.

The rollers tend to mark Depron if I run mine too fast as the rollers 'snatch' the foam. I've also had to lower the z-axis velocity to prevent the foam lifting during plunges. I think a lot of people are going to need a 3rd pressure roller to cope with these faster speeds. I guess FFF doesn't show any of these problems?

For EPP cutting with a 1/16" bit i've found I need to have the Dremel on the slowest speed setting otherwise the foam melts to the bit after approximately 10mins of cutting. I'd be interested to hear how fast the Mk2 can cut EPP using the small diameter bits.

Mark, have you tried producing any of the 3D carvings on the MK2? If it can run at 200+ipm for those sort of tasks that that's going to be a big bonus!

One thing that I really need to implement on my PP is some sort of dust extraction system. There really isn't room inside the Mk1 to rig anything up, hopefully there's a bit more space available inside the Mk2. Milling pockets makes lots of dust, and i'd really like to have the small pieces of foam (that are too small to tab) sucked into the printer rather than getting stuck to the pressure rollers (which again marks Depron).

Sorry for all the questions, I love the look and ideas incorporated in the new machine, but i'm trying to decide whether I would benefit from upgrading.

Si.

 

firetrappe - When your Depron gets marks like that from something getting pressed into it,
OR when it gets a really big "mark" from smacking the ground or a wall - - - -
Just pour some boiling water over the offended area. The heat in the water will cause the foam to swell back to its original shape. IF it raises some "warts" on the surface, just heat a large tablespoon in that same pot of boiling water, then use the backside of the spoon to iron the warts down.

 

I just saw the Videos on the MK II. All I can say is WOW!
Here I am just starting to put together the MK I and it is already obsolete.

I had better get one of these MK IIs as soon as I can so I can get it together before the MK III comes out. lol.

I'd be happy to be one of the first to receive one.
You guys have done a great job of design and fabrication.

Seriously, when can I get one?

 

I need to understand:

I am associating the belt system in the MK2 as a bike gears/chains:
- you can go faster if you convert torque to speed (big front, small back)
-you can climb steeper if you convert speed to torque (small front, big back)

here, we see the Dremel moving at incredible speeds, and not missing any step. how is this possible?
I don't doubt the video, they must be legit, I just don't understand how it works...

The original steppers are puny, and can only deliver so much energy.
Even an unclear all thread can make them miss steps. and here we have the same steppers cutting 1/2 inch balsa at speeds the MK1 can never even dream of, even with better steppers and increase amps

Am I missing something. Are there any documentation of this belt system?
Please... curiosity killed the cat, but i might be next !

I am still undecided if i should buy a MK2, or a fireballCNC, or both.
I think I am hooked. Will there be a discount for previous customers?

 

I don't know the details of the MKII as yet, but if we assume that it uses a large gear on the stepper motor and a small gear on the all thread shaft, I think it is explainable.

For example, In order to turn the all thread 1 revoultion with a direct drive system, lets say you would have to apply 8 steps.

If we instead apply a large gear to the shaft of the stepper motor and a small pully on the shaft of the all threaded rod, those same 8 steps could turn the all thread 10 times for each revolution of the stepper (depending on the gear ratio).

Stepper motors produce more holding power and torque at lower RPM's. As the number of steps increase, the holding power of the magnets decreases. Slower speed translates to more torque.

Having a large gear on the stepper drive a small pulley would allow the all thread shaft to turn more revoulutions thereby giving you more speed. At the same time, you get the added benefit of more torque because the stepper motor magnets work best at slower speeds, unlike in the bike example you mentioned.

The down side to this is that you would loose some resolution. 1 step would result in a movement of say 10mm with the gear system versus 1 step of movement producing just 1 mm of distance with direct drive (assuming 1 revolution of the all thread moves the material 1 mm).

Again, I don't know if this is how the MKII is setup since we have not seen any video of the actual steppers as yet.

 

Thanks for the tip Dennis, i've never tried that before. I must admit that I don't build many Depron models, but I cut some kits for a friend of mine and his one criticism were the 'pit' marks all over the foam.

Flash, i'm not 100% certain, but I imagine that there's no threaded rods on the MK2. I imagine the belt drive is similar to the carriage on an inkjet printer. Maybe Mark can confirm?

Si.

 

Ahhhh! Interesting. Can't wait to see more pics of the MKII.

 

I love my original and don't really care about the speed as i am not selling anything or trying to make money off it.
I really, really like the hing setup. Any way to have your guy cut out a hing deal that can fit on the side of the existing cutter?

 

i think that printer like idea would create a lot of play .... i might be wrong

 

If you make the pulley in the oposit end from the stepper spring loaded, I think that there won't be any play. The print heads of an inkjet printer works that way. Mark, could you give us a hint? Please?

 

Wow! What an improvement! Speed was the only complaint I have with my printer - thought it is faster than cutting by hand. I've had my printer from just after release. Will there be any special deals (significant price cuts?) On MKII kits or even retro kits for us?

Hey Mark - these motors are still working good now! Thanks again for the service on that.

 

Mark, The MKII is absolutely amazing man! I was staring at the video slack jawed when I saw the 200ipm cuts with stock steppers. I also really like the new look, very aggressive, futuristic and professional looking.

 

Look inside any bubblejet or inkjet printer and you will see that they are belt driven. They are some of the most accurate pieces of equipment around. I think Mark is on the right track using belts rather than all-thread.

So who is it that's working on a MOD to get belts into our MKI units?

 

Cool! After seeing the MKII in action it makes me want to throw rocks at mine....

 

yes, inkjet printers use belts, but on the other hand, they are not having to fight forces generated by the material they are cutting

 

And a heavy gantry with the Dremel.

Yoram

 

Sometimes you just gotta tell people a lot of times before they hear you Randy. Remember, not everyone here has has the experience of ducking chips from a shell mill.