A quick question about your "box" type Y-carriage in this pic please... Particularly about the position in which the horizontal plates are bolted to the vertical plates....
The top plate is bolted slightly above the top of the vertical plates and the bottom plate is bolted slightly below the bottom of the vertical plates... If that makes sense.
Did you do this for a specific reason such as making the initial DIY build/squaring easier?
To make it easier to square you should mill a shallow slot into the back of the Y-carriage plate which holds the Z-axis bearings. This can then align to one of the smaller plates on the Y-axis to get Z perpendicular to Y. You can just about see what I mean in this picture, circled in red:
Which reminds me I never posted the pictures from when I changed the Z round rails to linear guides:
Using the indicator made aligning the rails properly and getting it to run smoothly trivial. Fitting everything in the small available space was less trivial. Hard to say how much difference it made to the performance of the machine, since at the time the MDF bed was the limiting factor and I think my spindle might be on it's last elbows...
I finally had chance to drill the array of M8 holes for clamping in my router bed. Here's the result:
I used a carbide drill since the spindle speed required for a 6.8mm HSS drill is too low for the spindle to have enough torque to cut efficiently, if at all. I ran the drill at 9500rpm and 840mm/min with flood coolant, which according to the manufacturer's recommendations is quite conservative, but still plenty fast enough. I didn't see any point pushing it harder as that would only increase wear on the spindle bearings.
Here's a video showing the process. Possibly the most repetitive video I've uploaded to youtube so far...
The Z-axis motor, not surprisingly, got pretty toasty but other than that it went well. I had to move the bed out to reach the whole length, so it's currently 360mm from the normal position. Just need to make the router cut a drain in it, then I'll put it back.
Forgot to say in the previous post...
Around the edge of the aluminium bed I've put 3x2", 1/4" thick aluminium angle. This acts as a barrier for the coolant, so to ensure it seals I put a strip of 1.5mm thick neoprene under each piece. I used my metal cutting bandsaw to cut the 45° angles, but the finish from this although not bad for a bandsaw, is still quite rough.
Bit of an unusual set-up on the lathe so I videoed it:
(Something wrong with the sound on the past two videos)
Hello, looks like you've got a fine machine there Jonathan! Good work, It inspired me to go the way with the bed-box-gantry type mill, if I get started with one on my own.
Usage: pcb, wood, plastic engraving, possibly some easy metals, maybe 3d printing?, 3d scanning? Bigger polystyrene works. I like the idea of the adjustable bed height for different jobs. I already have three industrial dc motors+encoders and two ballscrews I was planning to use. I was thinking of a machine capable of moving 800*700*300mm.
A couple of questions came to mind:
1. Where do you get all parts? Is there a standard online place with good prices/service? Guides, ballscrew, bearings. Saw that Hong kong was mentioned.
2. I was thinking of moving the gantry with two rotating ballscrews and one motor. Long
gearbelt to sync the screws and have the motor directly on one screw. Whats your thought about this? I think I'm ok with a 1/10 or 1/20 mm milling accuracy. (I don't think I can build the complete works with greater tolerance)
If you use two motors the available torque is greater, so you should get higher acceleration and top speed, however it will work out a bit more expensive than one motor and a long belt. I don't consider one motor stalling and the gantry racking a valid concern since if your machine is tuned properly, and you shouldn't be running it if it isn't, then that should never happen. On my machine I had little choice since with the current gantry design it's impractical to route a timing belt to link both rotating nuts.
In other news, I have made and installed the drain for the router bed so I've been cutting with flood coolant. I fount that one corner of the machine is ever so slightly lower than the rest, so I put the drain in that corner so the coolant flows. A week later I discovered the reason for this corner being lower - there's a crack in the floor and it's sunk down!
The drain is fairly basic, just two parts I made on the lathe to hold some fine mesh, which is easily replaced:
After running for some time:
Video of cutting with flood coolant:
Did you source or mill the aluminum support for the guide rail?
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