Waiting for my mill

[pedwards2932]

Nice.  I am going to try it with the original bracket first just so I can get the machine running.  I have run into that several times with printing where things are too tight so I have started to print out a test section with the hole to see if bearing or whatever fits and adjust till I get it right.  Does it really need 70% infill?  I guess that makes it stiffer just not sure if that is where the flex is occurring.

[Zax]

I'm sure someone has the full CAD/STL file for these machines, surprised it's not posted somewhere but I haven't found it - YET!

[ggallant571]

If you can warm the part being inserted the plastic may like you better.

[wild.bill]

Here is what I used for speed control
[url][/https://www.amazon.com/dp/B0797NBC79/ref=dp_prsubs_2]

[Zax]

and if you want to wait a while... https://www.aliexpress.com/item/PWM-to-Voltage-Converter-Module-0-100-to-0-10V-for-PLC-MCU-Digital-to-Analog/32834921874.html

[Stonemull]

I was going to suggest a few posts back that optical isolation would be a good thing and possibly necessary, these controllers rectify the mains so there is no mains isolation to the actual motor, there is a small transformer in the control section but I don't believe it is a mains isolation transformer, I am yet to fully check it out but I was intending to make a spindle controller using an optical mosfet (I forget the part number but I have a few).
I wrote a review up somewhere here with some internal photos.

Edit: found it, looks like I decided it was isolated and opto coupled,

Spindle motor arrived .. now to assemble a machine around it
 https://r.tapatalk.com/shareLink?share_fid=2012650&share_tid=2842&url=http%3A%2F%2Fwww%2EBenboxLaser%2Eus%2Findex%2Ephp%3Ftopic%3D2842&share_type=t

I will double check my findings but if that is the case then a couple of resistors is likely all that is needed.


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[pedwards2932]

Got my new spindle in.....plan to print the holder for it this weekend so I can put this beast together.

[pedwards2932]

Well I got it apart kinda a pain.  Looks like you can push the bearings out.  Not sure how to get the threaded insert out?  Also not sure how to install it in the part I printed.  Any suggestions?

[Stonemull]

I just used a punch and pushed it all the way through the block, there is a lip stopping it for about  2mm the 'short' direction.

To insert I used the threaded rod to make sure it went in straight, just gently tapped it in.



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[pedwards2932]

Almost got everything ready for assembly.  I was thinking of heating the threaded insert so it would melt in place.  I also found this: https://www.thingiverse.com/thing:3221782   Looks like a really beefed up installation.

[pedwards2932]

Well I got it together not sure how well it will work....we will see.  Not happy with how tight the thread insert is.....I didn't heat it but pressed it in.

[Stonemull]

Thats why on the one I designed I have holes for optional locking bolts for the bearings and the fixed bush.

I need to redesign the damn one I printed,  I measured the distance between the holes on the aluminium bracket I got with my motor and made sure the 8mm rods on the Z would fit inside them if I used through bolts .. except I forgot about the 16mm bearings. so my bolts impinge on the bearing space.

this has made me look into buying SBR10 or SBR12 rod for the x and maybe upgrade the small Z distance with a longer version, except I am trying to find data on the graphite bearings instead of the usual linear bearings.

picture is with the supplied aluminium bracket, the bolt holes from that hit the larger hole for the z linear bearing though (looking at making that brown piece currently, the green piece I already have)

[pedwards2932]

I was thinking of doing something very similar as the part I printed from Thingiverse seems like the position of the holes where the bearing goes is slightly off so when I put the rods in I had to force them a bit so I don't feel like they move smoothly.  I may just design a piece that I can bolt the aluminum piece that came with the unit to it.  I may try it the way it is because it does work just not sure how much extra effort is needed from the motor to move it up and down.  Did you look at the set up from Thingiverse on the link I included?  https://www.thingiverse.com/thing:3221782

[Stonemull]

i had a quick look. you might have printed the different parts on a different axis on your printer ?
not all printers have the steps correct even, mine came with a default of 81 steps/mm on X and Y, which is wrong and I changed to 80. (3200 steps per rev/ 1 rev  = 40mm, 3200/40 = 80)

I forgot to mention a couple of things earlier, firstly I printed 19.00mm holes for the the 19.00mm bushes despite knowing it would be too tight as I noticed the latest cura has a new option under "shell" called "horizontal expansion" .. you can apply an increase/decrease in size to all polygons on a sliced layer. if set to +.1mm then a 3mm hole will print at 2.9 (or 2.8?), so its the opposite polarity to what i would expect.
The other thing is that PLA shrinks by around .3% after printing, so in theory a 19mm hole should be modelled at 19.057mm (19 * 1.003) ABS is double that at around 0.6%.
A vertical hole is smaller again unless settings are spot on as the the extruder pulls the molten material into the hole while doing a lap, single degrees in temperature can make a difference here. So yeh, I should have printed at 19.1mm probably, I had intended to try the shell offset but totally forgot about it.

[pedwards2932]

Hadn't thought of that.....I think what I will do is since it is a 3hr print is I will print enough layers to make sure everything is accurate and use a lot less infill.  Once I know it is correct then print a final product.  My bearings pressed in nice and tight but I felt like the threaded insert didn't have much to hold it.  I think when I redo this I will use some super glue when I press the threaded insert in.  I also have never really checked how well my printer is calibrated so I guess I should do that as well.