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The Meticulous Z-Axis


#41

That’s okay, I can relate. No pressure. :wink:

Not sure which is worse, not having a working machine set up or having a working machine I can’t get to. :upside_down_face:


#42

Looking good.

I am really glad you did this. It places a more scientific number on the need for dust collection air flow.

No kidding. I feel like I spend more time cleaning up dust than doing productive work.

After the linkage is raised up, it looks like there is more than enough room for the dust collection port. You could probably bring it back in and down some.

I like it. Good thinking.

Another thought. I have been thinking about the CG being too high. One simple way to lower the CG; increase the diameter of the bottom sled. Even though it needs to stay reasonable, another inch or two of diameter of the bottom sled would bring the CG down quickly.


#43

After having some trouble with the stock z-axis kit I ran across your design and really liked the idea. I was rather impatient and didn’t want to wait for ordering a proper set of rails, so I decided to make a prototype using cheap parts from the hardware store.

I bought some 3/8" smooth rod and 1/4" threaded rod and drafted something in fusion 360 based on your design. I’ve got it built and it seems to be working ok, though I’ve only had time to cut one small part with it. It has a lot of room to be improved, (need to cut the threaded rod down for one) but I really wanted to get my Maslow working fully, so I cut a lot of corners. Here’s a couple pictures of it:



#44

Understandable, although I did post a link above (and in the bill of materials on the garden) for an Amazon link which shouldn’t take quite as long to show up.

But what you’ve have will most certainly work! Great build! And it serves as a reminder than it’s definitely possible to build a prototype with stuff you can find at the hardware store. In a way, it reminds me of Tom Sanladerer’s Prusa i3 clone, “Dolly”, where he did something very similar with threaded rod.


#45

Maynard, how did you go about securing your HDPE? We have the exact same thing and don’t want to screw it up. I’ve thought of scuffing a side with 80 grit sandpaper and then securing it with 2 part epoxy? Was trying to avoid screwing into it. I’ve also read that you should / can lightly burn it with a blowtorch on one side? But that sounds scary and I don’t want to mess it up. Thanks!


#46

I used short wood screws to secure it to the bottom of the sled. I heavily counter-sunk the holes so that there was no chance of the wood screw coming in contact with the worksurface.

Epoxy would probably work as well, but then it would be permanently part of the sled. I’ve never taken a torch to the material, I just sanded it up to 400 grit where I needed to touch up the surface.


#47

Sorry development got delayed. The remodel is going into high gear and I haven’t had as much time to Maslow as I’d like.

The new dust chute was a test of my modeling skills. I wanted to establish this section down the chute:

image

Which gives us a section 46.488 mm (1.82 in) by 76.2 mm (3 in).

A = (1.82 x 3) * 28
A = 5.49 * 28
A = 153.74 CFM

I would have liked to get 190 CFM, but I was hitting the limits of the clearances I have under the router. It does provide enough flow for a 2 1/2" hose (140 CFM). I added a round opening at the bottom to fit that size hose.

PS-20180501-NewDust_1

And then added all the additional features to mount it to the sled and mate it with the hood body.

PS-20180509-NewDust_6

I’m going on vacation to Italy tonight, however, and will be a little too distracted to make any more progress. The Fusion 360 model is available, so if anyone wants to dig in and make their own nests and prep the stl files, feel free!

Arrivederci!


#48

How does the new throat piece align against the cut out section in the sled base? I remember you had cut a section out of the sled base to make room for more airflow. It looks like the volume created by cutting out that section is not being used.


#49

Right now, the only things that are missing here, as I see them are as follows:

  1. There is no mechanism to tighten and loosen the belt. I am not confident in whether or not it will work without that mechanism
  2. Availability of the dust shroud. I would either need to buy one from @MeticulousMaynard or make one myself. I do not have a 3D printer, so it would have to be ad-hoc.
  3. This one is probably a softer need. I would like to consider a larger diameter for the router base plate. I know there are default dimensions that have been used, and are known to work, but looking at the photos, the baseplate looks small in comparison to the z-axis.
  4. Time. I have young kids who have a talent at consuming all my attention. Any progress thus far has been fueled by nightlight and coffee.

#50

Posting from Florence, Italy right now, so I don’t have access to my more powerful computer that’s capable of running Fusion.

Yeah, that’s a good point. I had been fighting with the design of the dust chute for a little bit and hadn’t considered how the chute and sled were interacting as much. It will fit in the opening no problem, but I could probably clean up that cut-out to follow the opening of the new chute better.

I thought I had talked about this earlier in the thread, but I can’t find where. There really isn’t a need for a mechanism there. First, timing belts aren’t as finicky about tension as say, a flat or V-belt. Second, the motor can be positioned off to the side to apply enough tension to ensure that the teeth grab without slipping. I do want to make up a new bracket at some point that allows the motor to slide side-to-side to get a bit more adjust-ability. However, it should be the sort of thing where once you set it, you really don’t need to mess with it.

Hey, at least the new design uses less parts. :wink: I need to run the new chute through my slicer to get a good sense of how much I need to charge for it. I’m imagining that it’s large enough now to take a few hours to print, so it might be a little expensive. It would really help if I finished up my Prusa i3 clone, it’s such a better printer than the DaVinci I’m currently using. Unfortunately, the chute was designed for 3D printing, so it would take some re-engineering to use CNC to make it.

The center piece could be machined from MDF or plastic, although a plastic one would be a little expensive. I had originally designed it to be Maslow-able.

Alternatively, you could always buy the part from a CNC service like shapeways.com. Admittedly, most of the print services are quite expensive. The dust chute for instance is $103 on Shapeways, and generally my prices are about half of what they charge.

While it’s not by much, the sled is 1 5/8" larger than the stock size (it’s actually about 19.6875" or 500 mm). You have to be careful with making the sled too large, however, as you can run into issues at the bottom of the machine. I have 11" from the bottom of my work surface to the floor of my shop, so I can’t go above 22" in diameter without hitting the floor when trying to cut at the bottom.

It would not be hard to make the sled diameter larger before running the parts, however. You’ll just have to re-nest everything to fit.

We all have a short supply of time. I haven’t even been able to use my Maslow for months now thanks to the remodel. Not to worry, though, because it’s really going to come in handy when it’s time to make the built-ins and do the finish work.

I did design the plywood components to be fairly straight-forward to assemble, so it shouldn’t take too long to build. I would also like to add in all the mounting holes for the linear guides and such so that there isn’t any layout that needs to be done to put this together. Mind as well let the robot do the work!


#51

Thanks @MeticulousMaynard. Just a few more comments.

For this piece, and this project, even $50 is a above what I would like to pay. For this part, I would like to pay somewhere in the $10 to $15 range. I wonder if there are any alternatives or simplifications which could bring the price of that particular part down.

  1. Could it be made shorter, mounted to the back of the z-axis? It would be like a surface mount, where the flange is vertical, and screws protrude horizontally into the back of the z-axis. It looks like it could be made a few inches shorter with this modification.
  2. Could the ring part be made out of wood, cut out on the Maslow?
  3. Could the bottom part of the shroud be eliminated, such that it screwed to the plywood? It would seal against the plywood, and use the plywood to form the bottom part of its structure.

I don’t want to be cheap, or try to put you out of business. I know this is the part where you stand to make money. $50 is just more than I would like to pay.


#52

remember, the person may not have a working maslow to use to make the parts (at
least not to great accuracy)

I have a home-built CNC that we used a wooden motor mount on, and we had it
crack (and as a result, had the router throw itself around the shop, bending the
shaft of the router) I would not recommend wood for that part. Vibration and
humidity changes over time can cause it to crack.


#53

I think we’re talking about a different part. I am talking about the dust shroud, which has no structural role.


#54

Sorry for the delay, I just landed back in the US last night.

@Joshua I read your post when it first posted, but I’ve been giving this a good deal of thought. I do prefer the 3D printed solution to the dust collection because (I think) the smoother internal surfaces will give better flow-rates. And I really like 3D printing. >.>

However, I think that there should at least be a Maslow-able option. I came up with an idea to make it out of stacked plywood. The radius’ed part of the dust chute could be cut from several profiles of 3/4" plywood. I will have to draw it up to make the idea clearer. I have my doubts about flow-rate and how well it would “seal”, but it should be good enough to work. More importantly, it would make an option for those without access to a 3D printer.

@dlang Are you referring to the router mount itself? I had concerns myself about how well plywood would work for that. I figured that Baltic Birch would have continuous layers of ply so I didn’t get any weaknesses. I would ultimately like to make it from aluminum, so that should be stronger.


#55

Yes, I was talking about the router mount itself. when you have a good slab of
plywood, there aren’t going to be problems, but when you have a ring that needs
to fight tight around a high power motor and needs to be thin to clear other
things…


#56

Is there any draw back to buying the higher tooth count to speed up the z axis?


#57

None that we know of. The biggest risk with the highest gear ratios is that the Z-Axis motor might stall while trying to lift the weight of the spindle. At this point, we’re not sure if this is an issue, as we haven’t gotten the hardware set up enough to test.


#58

Hey @MeticulousMaynard. Long time, no post. I was on vacation, as well.

Regarding the Maslow-able shoot, I would keep it simple. I would make something like a box with one hole to insert the 2.5" hose, and one side missing to form the inlet to the dust shoot. It is possible to create a more optimal profile, but this should work. At least it could be a temporary solution which frustrates the user until they are willing to spend money on a more optimal 3D-printed version.


#59

So I did a quick and dirty version of a plywood chute. It needs a couple of details resolved before even thinking about making the parts, but I wanted to showcase the idea. I still have my doubts about how well it will work, and how easy it is to make, but this is the basic idea:

Side Section:

Back 3/4:

Front-ish:

In the assembly (note, this still needs clean-up):

image

So you can see that this is primarily tab-slot construction. The arc’ed sections would be cut flat on the Maslow, then stacked and glued. The holes in it would be for dowels to help locate and secure the parts together. They are made from 3/4" plywood. The rest of the parts are 1/4" plywood, with the exception of the back piece which is 1/2". I wanted to make sure that there was a bit more meat there since it is where the dust hose mates.

My biggest concern with this is that there are really thin sections that might blow out or snap during use. The arc’ed sections in particular are only 1/4" wide at their widest, and taper down to 1/8". Would MDF be a good material for this? I have my worries about voids in plywood here. I want to make that part beefer, and quite honestly, I may try to strengthen it by adding more material to the outside of the chute.

Or I could simply use a 1/4" piece of plywood, tab and slotted into it’s neighbors, and put it at an angle to leave enough clearance below the Z-Carriage.

It’s not going to have the same flow capabilities as the 3D printed version and I still see that as the better option.


#60

How are you going to get those tabs to be perfect fit? Won’t you lose quite a bit of air flow there (where your top and sides are mated to the back piece)?