Thanks. 6 rods to go and I will have the frame done.

spacexula Wrote:


"He doesn't seem to be a scam, he is just selling a
VERY flawed product, aka a printer that doesn't
print, and might NEVER print in the form of kits
that he has sent out to date. When you sell a
product in public, you open yourself to reviews"


I'm beginning to agree with this statement, It's looking a lot less like a scam on James' part, but it still does look like he's rushed into selling the kits before they are proven to work.

Time will eventually tell the tale, let's just hope there are no major hiccups between now and then for anyone involved.

Edited 2 time(s). Last edit at 03/11/2010 01:17PM by Kelly.

@Jeffrey - One note I have from when I assembled my frame... it might be a good idea to get some regular washers to put between the lock washers and plastic parts. I was leery of the lock washers against the plastic, but did it anyway. The few that I had to loosen to adjust really dug into the plastic and tore it up.

Just food for thought.

Buzz

thanks for that feedback, the lock washers are for resistance from the bolts loosening, but i will change that.

If you need lock washers against a plastic or wood surface, the best bet from my experience (in the arcade industry), is to put a regular washer between the lock washer and the surface. The way I've seen this usually done is:

(nut) (lock washer) (washer) (material(s)) (washer) (lock washer) (screw head)

This tends to get a very tight lock, and I haven't experienced loosening when this is done properly (including parts that customers are directly messing with - so roughly similar amounts of vibration and more abuse then equipment in this situation).

I've changed the kits i currently have to the regular washers. the plastic has enough flexing in it to compress a tiny bit, just don't over tighten. mine i tried not taking back apart, so i was fine using lock washers, but I'm willing to change them. it's been done. even the flat washers will leave an indent in plastic, just it will be circular rather than a sharp indent from the spring, i do include lock washers as part of the y assembly. use lock washers there, otherwise it will loosen. having too many washers is not desirable because this makes the machine smaller inside. Also the current x-bar design will be posted on thingiverse tonight for those interested. the design does not require a flywheel like the y axis does because the friction and weight are much lower.since removing it it frees up another 40mm in the x direction.

also i found out how to enable pull up resistors in arduino, so the limit switches are easy just wire them up to gnd and pin 10,11,12. whenever the min switch is pressed the device pin will go low. this is part of homing i show in a recent video. so recent videos are with arduino usb and reprap host software. i plan to show it working this week. this is different from before where i had it working with mach III.. just keep looking at my videos. you'll see the device in action.

@jeremyl - That is exactly how I did mine

one thing I found for the y axis is if you put 4 extra bolts on the frame where the squares connect to rods you can adjust them easily. see pics on my website and look closely at where the y axis rods attach to the frame and you will see what I mean.

[endgamebooks.com]

[www.thingiverse.com]

xbar uploaded.

James, you mention the following specifications on your webpage:

x 165 ipm 70mm/s positioning system .00025inch .006mm
y 165 ipm 70mm/s positioning system .00025inch .006mm
z 20 ipm

extruder speed. (1-100mm/s) +/- .1mm error

Have you achieved this, or is this simply your theoretical max your kit can do once everything is tuned, patched, and tweaked properly?

If you've achieved this, congratulations ! Make that clear on your page.

If that's happens to be your theoretical max which you think you'll hit in a few months, please make that clear on your page. It's extremely ambiguous right now, and I think this may be confusing your future users.

I believe it is essential for sellers in this marketplace to be crystal clear what their kit currently can and cannot do.

A number of people have for a current snapshot of your kit's performance and ability. I'd like that as well. Please take care of this minor matter in the next few days by printing a frame vertex or similar, with a video.

I think if you do that, it will clear up a lot of the confusion and then we can focus on sales, R&D, world domination, self-replication, and other stuff.

To reiterate, I'm happy that you choose to participate in this marketplace. I just want you to take a minute to make it clear and simple what you are selling.

If it takes 2 hours for your kit to print a frame vertex ... good to know! Post that. If you do it in 30 min, even better to know! Post that.

---

-Sebastien, RepRap.org library gnome.

---

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

The latest video shows the extruder pushing out PLA - it looks like the PLA is still coming out WELL after the motor stops (albeit at a slower speed) - which you refer to as 'drooling.' From watching the video and my understanding of your design, even with a reversed motor this is going to be virtually impossible to eliminate. This was one of my early worries, but I assumed you had it under control. I had no idea you didn't have a properly working version of your extruder when I made my order.

From what I can tell, this problem simply is unworkable in your design - the hose the filament runs through stores too much energy (it flexes when the motor pushes the filament in - when the motor stops, the hose still produces considerable force on the filament while trying to flex back into a 'natural' position).

I am highly skeptical that simply reversing the motor will be enough to quickly stop and restart the extruder.

Showing the machine extruding is nice - showing it actually making something is what we need to have a clue if this will actually work.

I had no idea you didn't have a properly working version of your extruder when I made my order.

If James doesn't clear all this up in 2 days or so, I think it may be best if he sells his products as separate parts. {Molded pieces and Rod}, {Steppers},{(Experimental) Electronics}, etc.

This will allow him to cover his costs, while at the same time being clear to his customers that he is selling different parts of a toolchain.

But if anyone sells the full toolchain in this forum, than they need to demonstrate operation of that toolchain. Anything else eventually leads to buyer-seller conflict, which I have no desire to mediate or arbitrate.

10KUSD seems to be changing hands here, and I think we all have a responsibility to be careful with our funds.

---

-Sebastien, RepRap.org library gnome.

---

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

I got my y axis working. here is a link to the video of it working.

[www.youtube.com]

I will try to get the z axis working tomorrow or the next day but I need to finish my enclosure first.

I can't help fight the feeling that I am gonna get shocked with open circuit boards.

Jeffrey: everything on the Reprap is low-voltage DC - I highly doubt you'll get a shock, unless you have wet hands when you touch something. The highest voltage in this version of the Reprap is 18V DC from what I can tell - nowhere near enough to cause any real harm under normal circumstances.

Again, just don't be wet when working with it, and you should be okay - and if you are worried about it, Reprap a cover for the boards!

jeremyl,

It is possible to greatly reduce the PLA drooling using a stepper motor driven extruder that reverses at the end of a line segment and then advances at the start of the next. The bitsfrombytes RapMan extruder and firmware does a good job of this, for example. Drooling of PLA is still an issue at the start of a print while the extruder heats up.

The issue with the hose that the filament runs through (referred to as a Bowden cable elsewhere in the RepRap blogs) supposedly can also be overcome by reversing the extruder the correct amount. At least a few people have Bowden cables working, so I imagine it's possible. I hope to try a Bowden cable myself at some point.

However, I've also seen it mentioned a few times that it is difficult (impossible?) to get fine extrusion control using a DC motor, like used on the makerbot and it sounds like this kit. I am just going by what others have posted in these forums and in the various blogs, but it sounds like this kit would work much better with a stepper driven extruder.

Jeff

Thanks for the update video, looking forward to the rest as they come in.

Edited 1 time(s). Last edit at 03/08/2010 11:03PM by Kelly.

Zomboe Wrote:
-------------------------------------------------------
> it sounds like this kit would work much better with a
> stepper driven extruder.


It is my understanding that this extruder is stepper driven. This video shows James assembling the stepper to feed the extruder.

Reversing should take care of the drool.

Hmm, watched stepper motor video, not sure what to think so am asking a couple of questions.

How do you define "Not so tight" and "Super tight" in ft lbs or inch lbs of torque?

Is it a little odd that he's using pliers instead of wrenches to tighten the nuts and bolts?

In my experience, trying to use pliers in this way results in the loosening of parts, joints and connections over time as a machine vibrates because you can't tighten parts with a pliers like you can with a wrench. This also results in stripped bolt heads and nuts.

The most questionable part of the video was the use of those large washers he uses to grip the rod to hold the motor mount in place, those will bend eventually and won't keep a very good grip on the rod because there isn't enough surface area contact between the washers and the rod. A simple plastic backing piece with a groove cut out to fit the rod inserted between the washer and the motor mount would work wonders for making that a solid joint that won't slip.

@Kelly -

How James tightens his bolts is one thing... I tighten mine with wrenches. Since he is selling the kit, not a fully assembled unit, this is not an issue to me.

I have already made a few changes to his printer as he had designed. The extruder-grip method is one place I plan on changing...

At this point, I am just waiting for his extruder kit to ship. I am not overly concerned with his design, since I will most likely be changing it. However, I cannot change it until he ships it...

Looking at his PLA extrusion video there is no way that it is pushing 100mm/s. There would be about 5 inches of plastic coming out of the nozzle every second. I am fine with this - even if his website says it can do this.

At this point, I just want the motor, heater, tubing, and mounting parts. I will take it from there. I am almost done assembling my frame. I will post pics and comments when it is done. Hopefully, the extruder kit will ship before then.

Buzz

Edited 1 time(s). Last edit at 03/09/2010 02:34PM by buzzard192.

@Buzzard192

Understood, I'm sure you'll be able to change certain aspects of your kit to suit your needs.

I was mainly commenting on the odd nature in which James vaguely gives instructions on each step of his assembly in the videos as well as the odd and improper choice of tools that he uses when the proper tools are readily available for a very cheap price at any department store or hardware store.

Yeah, the video does seem to show his setup extruding the PLA at speeds closer to 25-30mm per second.

Is it possible that the stepper motor is moving at 100mm per second but the PLA is dragging or hanging up in the mechanism resulting in the lower actual extrusion speed?

That might also explain the drooling if the PLA hangs up while operating, then releases it's stored up tension after the stepper motor shuts down even if it does reverse it's self.

Jeremyl may be correct with his earlier post about the drooling issue.

Edited 2 time(s). Last edit at 03/10/2010 02:02AM by Kelly.

James emailed me and said he'll have a video up in a few days.

---

-Sebastien, RepRap.org library gnome.

---

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

I have been working with James on a little problem I am having. I thought I would fill you guys in.

I wired my z axis and have been having trouble getting it to run properly It works when I hook it up to the y axis but when I hook it up to the z axis it only buzzes.

I tried adjusting the voltage on the cnc board (read the manual that is on his website.) I also tried turning off micro stepping.

I suspect that It is either a software problem or that the board itself is not functioning properly.

I think I am going to hunt down the board manufacturer and talk to a rep there and see what they say. Anyways other than that small problem I have everything working well.

I still have to finish my enclosure and a few other minor things then I will be waiting for the extuder and x axis parts.

I hope this is not a structural problem..

Keep me posted please.. don't know if I might run into the same problem..
Although James showed it all up and running with 3 axis..

Let's hope it is just a software problem..

Its not structural I can swap the y and z axis and it works fine. worse case I can just change the code for the adreno board and it will work fine. on another note I just broke my only $%^#%$^@#@ drill bit so I got to go buy a new one so I can finish drilling my holes for the enclosure.

James had me swap pin 6 and 7 to 2 and 3 on the arduino board and the z axis works when I jog the x axis on the setup program. This tells me that it is probably an issue with the software.

Jeffrey Olijar Wrote:
-------------------------------------------------------
> James had me swap pin 6 and 7 to 2 and 3 on the
> arduino board and the z axis works when I jog the
> x axis on the setup program. This tells me that
> it is probably an issue with the software.

I am not sure what software you are using but if you are using ReplicatorG, for example, the max feed rate for the Z axis is different for the XY axis and if your machines.xml file is not set correctly then it can default to too high a rate for that axis.

Thats my guess anyway. The Z axis is just trying to drive the thing too fast.

-- Chris

That could be. I am using his test program at the moment. I tried to use the rep rap java software but it says cant recognize /dev/ttyUSB0 I found where to change it but I dont know what to change it to.

I used COM3 instead of /dev/ttyUSB0 and it worked. I can move my axis with the reprap software and everything appears to work. I am going to run some more tests and get my wiring set up exactly as I want it.

Here is my machine so far. I have been posting about it as I build it here [endgamebooks.com]

I am curious to see pictures of the other people who have received their machines.

If any of you need help feel free to email me. I have my machine more or less done mechanically. I am struggling with the software portion, but I think that is because I am a moron when it comes to computers. (although I am pretty good at autocad)

I received my kit yesterday. Taking inventory is a little tough, as Jeffrey pointed out previously the "inventory drawings" are printed very light. The kit is missing the x-axis and extruder as was expected. My kit also seems to be missing one of the square pieces for holding on the y-bars. I emailed James about this.

Also, I don't seem to have any of the 5/16th nuts and only a handful of the 5/16th washers. This is not a huge deal since I have these on hand already.

I hope to get started assembling (as much as I can) this weekend and will post any relevant discoveries.

Also, my box was pretty smashed up and had a gaping hole that was haphazardly taped shut, presumably by a postman somewhere along the line. This might have something to do with my missing pieces.