Techzone Lasercut Mendel: X, Z Axis parts question

I recently bought a Techzone Lasercut Mendel kit and started putting it together but not sure if I got the correct X axis rod/motor mount parts and/or the Z axis rod/motor mount parts.

Check out the pictures:



It looks nothing like the pictures on the assemble wiki page or assembly blog page

They actually almost look like parts for a Lasercut Huxley variation??

Anyone can confirm that I received the wrong part or if not, how to assemble with these "different" parts.

Thanks
Jack

The wiki is most likely outdated. It's very common here.

Those are the same parts that I received.

The X axis ends are different in that the belt only goes around 2 bearings at the motor end, and doesn't wind as tightly around the motor as it did with the older version. This helps to relieve some of the stress on the belt so that it lasts longer.

The Z axis no longer has a separate idler for adjusting belt tension, but instead the tension is adjusted by moving the motor.

Hi Ron,

I figured out how the X axis works.

But I'm having trouble with configuring the gears and bearing on the Z axis where it can get enough tension.

Check out the pic of my Z Axis gear arrangement. My motor is at the "max tension" setting and there's still quite a bit of slop on my belt.

My belt is 960mm long continuous (480mm half length).

Did I get a belt that's too long or is there another config for the gears, bearings and motor that I should entertain?

Thanks
Jack

UPDATE

So I found this pic of the bottom of Ulrich Glimm's LC Mendel build.

But in that config, there is still too much slack in the belt even when the motor screwed down at "full tension"

So I managed to arrange a couple of bearings and motor gear as shown in the pic attached -

Not too happy with how much the belt kinks around the 2 bearings but cannot think of another way.

Comments? Thoughts?

Thanks
Jack

It looks to me like you're z-axis belt is sized for the old arrangement, where there was an adjustment idler on the side opposite the motor.

I'd say you should contact TechZone, and ask them to send you the proper belt.

jackp510-

I had a similar problem you have with the belt begin too long. I installed an additional pulley to tension the belt and complained to the very unresponsive and unhelpful people at techzone. The sent me a link to a website. Eventually they agreed to take picture for me. Weeks later I got an email saying they were trying to assemble a kit to take pictures and realized they sent the wrong sized belt. So they sent me a shorter belt which I never installed because I managed to rig the longer belt up and was working.

NATE

Hi Everyone,

We had the same problem with our Z axis belt and had to move things around quite a bit too. Makes me wonder why they don't seem to include the belt tensioning assembly that you see on some photos of their kits anymore

Our photos are here: photo 1 and here: photo 2

Jacqueline

Our Mendel in progress

I have the same Techzone LC Mendel as the rest of you in this thread, albeit with a shorter Z belt. It looks like I should be able to fit it quite easily with regards to its length (in fact if anything it's a little on the short side). My problem is with the clearance needed under the Mendel to allow the belt to run freely. I haven't seen any build instructions for the LC Mendel Z axis, only the photos in this thread, so for my starting point I looked at this setup from the "normal" Mendel:

[reprap.org]

In my case, in order for the belt to run freely below the Z idler, given the parts I have left over, the assembly list from top to bottom currently goes:

Z leadscrew (runs down through all the following)
Nut
Washer
Bearing (mounted in the Z idler box with the 3 M4 screws)
Washer
Nut
Washer
Nut
Washer
Nut
Pulley rim (wooden)
Pulley
Pulley rim (metal)
Washer
Nut.

As you can see, I've had to put in a pile of nuts and washers to space out the wooden pulley rim so that it stands out
just below the lowest part of the box so the belt won't snag. The problem with that is that the bottoms of the Z axes now stick out of the bottom of the machine by a couple of centimetres. I'd need some fairly significantly-sized feet to get the machine to stand properly, and the smaller bearing that sits near the motor to adjust the tension would also need to move down - requiring a longer screw than the M4x40s I have. Where am I going wrong?

EDIT: Photos of my current setup. You can only really see 2 of the 3 nuts between the box and the pulley, but it should give some idea of how I've had to space things to get the belt to run freely.

[i840.photobucket.com]
[i840.photobucket.com]

Edited 1 time(s). Last edit at 07/26/2011 04:36PM by electrodruid.

This is something that might need to be addressed on the Wiki regarding the Techzone LC Mendel: It keeps evolving as they often incorporate newer redesigns into their process. I've noticed several examples of this, but haven't had a chance to really fix up any documentation.

-There are still images of their wooden wade's extruder floating around, which they abandoned sometime before October 2010 in favor of a true printed Wades.
-Their y-axis bar clamps were a wooden redesign of the Sells ones, though I believe they are now making something like the Prusa clamps.
-The newer z-axis drive system you all have been describing here, seems to be something they've been doing with their huxley design, where the motor shifts to act as a tensioner.
-They also appear to have incorporated the alternative x motor bracket design, for less wear on the x-axis belt.

These sorts of things should be kept in mind by anyone building a techzone kit : What they send to you may well have incorporated some redesign, without any notes or documentation. I sort of wish they'd have a little blog or something where they could point these details out....

EtherDais Wrote:
-------------------------------------------------------
> This is something that might need to be addressed
> on the Wiki regarding the Techzone LC Mendel: It
> keeps evolving as they often incorporate newer
> redesigns into their process. I've noticed
> several examples of this, but haven't had a chance
> to really fix up any documentation.
>
> -There are still images of their wooden wade's
> extruder floating around, which they abandoned
> sometime before October 2010 in favor of a true
> printed Wades.

They're still shipping the wooden parts, at least to some customers. They sent me a wooden extruder in April 2011.

> -Their y-axis bar clamps were a wooden redesign of
> the Sells ones, though I believe they are now
> making something like the Prusa clamps.

That's what they sent me.

> -The newer z-axis drive system you all have been
> describing here, seems to be something they've
> been doing with their huxley design, where the
> motor shifts to act as a tensioner.

Those are the parts that I received - the belt they sent me was short enough that I needed to reduce the width of my printer by 1/8" in order to get enough slack to install the Z Belt.

> -They also appear to have incorporated the
> alternative x motor bracket design, for less wear
> on the x-axis belt.

That's also my experience.

>
> These sorts of things should be kept in mind by
> anyone building a techzone kit : What they send
> to you may well have incorporated some redesign,
> without any notes or documentation. I sort of
> wish they'd have a little blog or something where
> they could point these details out....

The biggest problem is that they seem to be more than willing to build up a kit out of whatever they happen to have on the shelves, and send it out believing that the customer can figure out how to make it work. Usually, it can be made to work, but only at the cost of much good-will.

If I had to do it over again, I'd go with printed parts, and source the vitamins myself. In the end, TechZone's kit didn't provide any real savings, either in time or money.

The lack of official documentation is indeed irritating. I thought that if I bought a complete kit I'd spend more money than by procuring all the parts myself, but save time. I think any of those time savings have been erased by the complete lack of documentation. I emailed them and got the same responses they seem to have been giving out since they started producing the kit, which is that they're "working on" documentation, but have not responded to any of my questions about when it will be available, or any of my more specific enquiries about the parts that differ from what's shown in the wiki. I've still got high hopes of finishing up with a working machine but I'm not convinced that the finished product will represent particularly great value for money, and until the documentation exists I'll be steering any friends who want to build RepRaps away from the Techzone Mendel kit.

Anyway, general awkwardness aside, I've muddled through okay. After some "WTF?" moments I was able to recognise the parts which are different to the wiki versions, and assemble them in a way that looks like it's correct. If people think it will be particularly useful to others, I'm prepared to disassemble my X and Z axes so I can photograph putting them back together for the wiki. Except first I need to solve my problem with the Z axis. Can anyone with a working Techzone LC Mendel with the new Z axis design show or tell me how they got the pulleys positioned so that the belt won't snag on the wooden parts?

electrodruid Wrote:
-------------------------------------------------------

> Can anyone with a working Techzone LC Mendel with
> the new Z axis design show or tell me how they got
> the pulleys positioned so that the belt won't snag
> on the wooden parts?

There need to be spacers between the large pulleys and the z-axis bearings. I'm not sure where I encountered it, but that was one of the things I managed to find documentation for. The LaserCut Mendel Assembly page directs you to Mendel_frame#Installation_of_X-axis, which uses a nut, and a stack of washers as spacers - I just used 2 nuts, and threadlocked them into place after getting the spacing right.

Hey hey,

Just to let people know I've had a fruitful couple of email exchanges with the Techzone guys. They have new documentation up:

[www.reprap.org]

Some of the dates seem to imply that these pages are actually quite old, but it's the first time I've seen any of them, and although they're not perfect they seem a lot better than anything I've seen before. With regards to my problem of the Z axes hanging below the bottom of the machine, I got this response:

Quote

We started by copying what we had done for documentation on the Huxley to build the Mendel instructions to make sure we didn't miss any steps, so that is why you saw some Huxley pictures in the section I haven't hit yet. We had a Maker Fair in Detroit this last weekend, so we have been busy getting ready for that and I haven't had time to get back to the documentation. I have my drive rods sticking down a little below the frame to give the belts plenty of space. I then put stick on rubber feet from a local hardware store to raise it up just enough to clear (it also helps keep the machine from vibrating its self off the table). Others have notched the boxes, but I prefer adding the feet. If we could find a decent supplier of those feet we would add them to the kit. I will be going to India on the 14th of this month, so I may not get time to finish the documentation right away.

So, the documentation might still be a way from completion by the sounds of it, but I got the answer to my question (namely "put feet on it"). I'm fighting with the electronics now, but in general I'm feeling a lot better about the Techzone kit after seeing more documentation and hearing back from them about the Z axis issue, so I thought I'd share