Saturday, 9 December 2017

CNC The build... part 2

Part 2

Following on from my previous blog a few people have asked what is the "Y" axis ? Hopefully I can explain ?

Overview

The CNC (Computer Numerical Control) converts a design produced by a CAD (Computer Aided Design) into numbers. These numbers are basically coordinates of a graph, and these numbers can then control the movement of the motors connected to 3 different axis of a graph, X, Y, and Z.
The router and cutter are connected to the Z axis.

X is the side to side movement
Y is the front to back movement
Z is the up and down movement

So in the last blog I said that the Bed Rails are used to hold the "Y" axis rails; which will be in the "front to back" orientation of the CNC. This will become clearer later on in this blog post with the aid of photos.

Side Plates x 2

Construction of a side plate for the "Y" axis are made up of a mounting plate, 4 "V" pulleys, 2 static and 2 adjustable, a stepper motor with GT2 belt pulley, 2 smooth idle wheels, and a few ancillaries. Series of photos shows the progress of the build.





V pulleys and idler wheels fitted


Stepper motor fitted

X Carriage Assembly

Similar build to the Side plates but in a rectangle extrusion with "V" pulleys, idler wheels, motor etc. But this will also support the "Z" axis assembly.




This part is a little fiddly, having stubby fingers doesn't help, and having to angle spanners to get a good grip on the nuts as these are recessed inside the "V" pulleys.



The adjusters for the "V" pulleys are small eccentric nuts as shown in the photo above, and these have to fit into the holes on the "X" carriage, unfortunately they don't fit? but with the aid of a small circular file to remove the coating from the main body of the carriage they now fit perfectly.



Motor and limit switch fitted...




"Z" Axis assembly

This holds the router and with a "lead" screw raises and lowers the router.



Attaching the top plate to the maker slide to the "X" carriage, and inserting the bearing and lead screw with a "GT2" pulley.



Mounting the "V" pulleys and adjusters to the router holder.




"Z" assembly now connected to the "X" carriage.

Gantry Rail Assembly

The side plate assembly now needs to be attached to the main "X" Gantry Rail.




A couple of drag chain brackets were also added to the side plates.



Before putting on the other side plate the "X" carriage and "Z" assembly is rolled onto the gantry rail.



With both side plates firmly connected to the gantry, we can now more onto the "Y" rails and attach the end plates, which in turn will connect to the bed rails as explained earlier...



Lots of small fiddly nuts, bolts, screws, etc this morning, but good progress made. Getting cold now, and a snowstorm is forecast for later on, so stopping for today.


Summary

Time on build today 4 hrs

Total build time 12 hrs








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