CNC BUILD PART 1 - Rebuild of a Chinese HGR20 Linear Carriage (reball)
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- Опубликовано: 12 окт 2023
- I received the first parts, and i wanted to check out the linear rails first.
The Carriages do not run all that smooth (at least a few run terrible unusable) so lets try to get them working better. i also ordered some balls from the UK with a Grade rating of 10, that means high precision. ill try them when they arrived. and order more if it works out. the current replacement balls are of unknown Grade... and material. but seem to work already much better then the ones it came with. i also removed the free metal dust i received with the bearings :) 
Хобби
made a mistake the replacement bearings where 5/32 of an inch and thats 3.96 mm not 3.69.... compared to the 3.98 mm the carriage comes with. the grade 10 chrome bearings i ordered are 3.97mm (according to them, i guess rounded of from 3.968) and that might be a nice in between size but also is a far higher grade then any of these so they should be more round. and have less wear. you can get them at simplybearings.co.uk
ill test them up coming week and let you know !
This is gonna get really popular
well i dont know :) the few that like cheap DIY CNC :) then again the materials are cheap...and hopefully they can improve on the quality !
@@joppepeelen like me hah! I am an engineering student in college who was looking to do a DIY CNC for senior design. This helps research a lot.
Almost lost it when you said "three point six", that would have killed the rails in a week... For linear rails, changing an internal tolerance by 0.01 mm is considered a HUGE change :) -but you meant 3.96 :)
I helped a friend install a shorter pair with a similar chinesium quality on his 3D printer, had to chamfer all railing edges, even the long edges. I also ran a 2000 grit ceramic stone over all the running surfaces on the rail, they had quite a bit of small surface damages you could feel with the stone. It got better, but nowhere near the quality of the Rexroth stuff we used at work :/
And check ALL the ball return channels on the guides by dropping a ball through them after washing, a blocked or damaged return channel can destroy a rail in a matter of weeks. A 10c plastic component destroying a 200Eur rail is no fun.
Cool to see a new project, best of luck!
It would not have killed the rails, i would have insane slop if i used what i said the bearings where hahah.
Well the rail looks pretty decent (i mean for what it is) the blocks on the other hand have far more troubles then the rail... the return plastics look decent but what i see is where the groove ends on the metal before it goes into the return... there is a sharp edge. and that wont matter for the balls going from metal to plastic. but it does for the balls going from plastic to metal (since it is a step upwards...) creating a bump. besides that the holes for the return path trough the block are drilled but not reamed... so i can see by eye its not smooth.
i indeed made a mistake reading the size of the bearings :) 3.98 is the original 3.96 is the replacement and i bought G10 bearings been 3.97mm so in between and far higher grade, and i think they might be the ones i use. then again i used second hand THK, IKO and REXROTH rails before, and i know these are not match at all. then again. prices for them new is 8-10 times as high. so making these good enough... might be more then enough accuracy for a DIY machine.
@@joppepeelen 0.1mm mismatch either up or down will cause the balls to slide over the rail in stead of rolling, and with hardened balls this wears grooves into the rail pretty quickly :) But if the blocks feel overconstrained, then -0.02 will surely work well. Thin oil and good wipers and I'm sure they'll work for many years.
I know we replaced rails after a certain amount of hours in our machines (packaging machines), regret I didn't grab ten or twenty when I had the chance back then :)
@AJBtheSuede o.o1
Hi, thanks for the video, do you have a link for the balls please...?
Not saying this work beter , because i had some that became to sloppy.... but website was simplybearings.co.uk
Who did you buy your aluminum rail from?
www.vallder.com/en/shop
Is there any way of honing or polishing in guide rails?, sounds a bit crunchy at best. Good luck.
well the inside looks good the return path (straight holes) do not :) looks to be drilled without any reaming/honing i can see rings in there,, instead of a even hole, really nasty :) not sure how much it matter though
well the rail itself seems pretty good.
I'm curious, what did those rails cost you?
The rail only is around 50 euro a piece carriage 12 euro a piece
@@joppepeelen Ow! That is way cheaper than I would guess! Dankje!