Printed DNA30 Bottom Feeder

[gdeal]

I was doing some measurements and assembling the most recent print from Sculteo. An important assembly step is to make sure that the mini connectors when inserted during the dry assembly are at the right height. While the Sculpteo print was done very,very well, there is always going to be some slight variances in tolerances. One area where a meaningful variance can occur is at the top level of the three piece internal assembly. I measured each part and the top two were off by about .2mm - greater in thickness than the CAD spec. While its really insignificant in the greater picture, this a key interface so the additive effect of the variances are significant. This will need to be dealt with if it occurs. In the picture below I use a .8mm paper clip to show the part as received and then after sanding the top. The mini connector should sit about .5 mm below the surface.

The top layer in the design was made slightly thicker than the other two just in case this effect should happen, so there should be no issue sanding material off. I did think about forcing a slightly thinner dimension into the CAD design, but if the variance goes the other way (thinner), it may be an SOL situation.

 

[OthatGuy]

What a are you guys that are awaiting your parts planning on doing as far as paint goes? Has anyone used rhino lining?

 

[Alexander Mundy]

One of those is printed backwards from the other!

 

[gdeal]

Ok...So I also sent an email to Shapeways over the weekend outlining the issues people were recently having with their printed parts and requested some formal type of communication and action. They responded today and asked that I pull together all the issues that people have had and provide them the detail including any pictures that they sent them and if any resolution has occurred. Some of you guys have posted and some may not have posted. If you have had issues with your prints (even if you got resolution) and want to get in on this, please PM me.

I think we can speak louder as a group. I dont know what they are going to propose as a solution, or even if they have one, but at least we have a pathway now with a senior person in the CS group. I have some examples, but the more real issues we can provide, the more compelling their response should be.

 

[gdeal]

One of those is printed backwards from the other!

Wise guy...

 

[Cool_Breeze]

Ok...So I also sent an email to Shapeways over the weekend outlining the issues people were recently having with their printed parts and requested some formal type of communication and action. They responded today and asked that I pull together all the issues that people have had and provide them the detail including any pictures that they sent them and if any resolution has occurred. Some of you guys have posted and some may not have posted. If you have had issues with your prints (even if you got resolution) and want to get in on this, please PM me.

I think we can speak louder as a group. I dont know what they are going to propose as a solution, or even if they have one, but at least we have a pathway now with a senior person in the CS group. I have some examples, but the more real issues we can provide, the more compelling their response should be.

Perhaps more difficulties will come to light when hardware arrives.

 

[gdeal]

Perhaps more difficulties will come to light when hardware arrives.

This is really for stuff people has already received. ie: broken parts, bent surfaces, abnormal print marks, wrong pieces, grossly out of spec dimensions, irregular dye coloration, etc....Stuff they should be man'ing up for and not making us jump through hoops for resolution or satisfaction.

 

[Rossum]

OK, one more wiring picture:

And then the moment of truth:

 

[Rossum]

I sanded that surface right flush with the connectors on my current build. I also took a bit off the corresponding mating surface on the upper. I haven't installed the magnet in the lower yet, but this build is holding together nice and tight.

Maybe I'm missing something, but I'm not sure how any material on these surfaces that's beyond the plane of the connectors is at all beneficial.

 

[gdeal]

I sanded that surface right flush with the connectors on my current build. I also took a bit off the corresponding mating surface on the upper. I haven't installed the magnet in the lower yet, but this build is holding together nice and tight.

Maybe I'm missing something, but I'm not sure how any material on these surfaces that's beyond the plane of the connectors is at all beneficial.

Only enough material so that the pressure when you connect the top and bottom is not on the connectors. It will sit nicer if the two larger plastic faces are flush while the connectors and the magnets are slightly recessed. (<.5mm). I dont know how much glue you use for the connectors, but I do it sparingly, so I try to prevent a pressure point which could pop them out. Same for the magnets.

 

[Rossum]

Only enough material so that the pressure when you connect the top and bottom is not on the connectors. It will sit nicer if the two larger plastic faces are flush while the connectors and the magnets are slightly recessed. (<.5mm). I dont know how much glue you use for the connectors, but I do it sparingly, so I try to prevent a pressure point which could pop them out. Same for the magnets.

OK, that makes sense.

In the build I just finished (except for still needing a bottle prepped) I've got the lower dang close to flush:

But the upper still has a bit of extra meat:

So the connector housings won't be pushing on each other.

 

[gdeal]

That looks really good Rossum.

 

[BobC]

Uwe, I notice you use all 4 connectors, can't you join the ground with the bat - on one connector?

 

[Rossum]

Yup, battery ground and atty ground are common on one connector pin. But you need a second pin for atty power (which is negative with respect to ground!). And you need a third and fourth for the Fire switch, which doesn't seem to be common with anything.

 

[Nautilusfan]

And then the moment of truth:

[/QUOTE]

And we have liftoff! Looks great!!

 

[BobC]

Got ya, forgot about the 2 separate fire connections

 

[Rossum]

Right, on the DNA30, most of us were connecting one side of the fire switch to ground. It doesn't look like that's advisable with the 40. Now I've very glad we went with four connector pins rather than the minimum three that we contemplated at one point (and that I put in my v3.0 "Franken Build" back in June).

 

[BobC]

Yeah, the 3.o with the three bullet connectors

 

[ValHeli]

what do you guys do when gluing internals? I want to do it in such a way that I can still take the whole thing apart without damaging it.

 

[Kataphraktos]

what do you guys do when gluing internals? I want to do it in such a way that I can still take the whole thing apart without damaging it.

I only apply CA to the bottom bit of the connectors (where the lip is) in the main internal assembly and sparingly on the lowest portion of the magnet in the main internal assembly, so it can still be taken apart if necessary with a minimal effort.