Random stuff, reduction, servo motors, ideas and thoughts

thefabricator03 wrote:

Two words, CNC Mill.

I am hoping to have one by the end of the year. From watching videos it sure seems to make making motor mounts and such a breeze. Need another part, just load the material and run the program again. I really cannot wait

yeah that's why i am building what i have so far. manual machining sucks takes so long just to make something. the down side to a VMC is price and travel restrictions. small parts like a motor mount you can't beat them. long parts suck to make when you have to work on it in sections. the more set ups you have the more chance you have for error to add up on you. industrial gantry mills start at about 150,000 for a base model. small VMC might be had for around 75,000. they are not cheap but are nice to work with.

I am looking at buying a new smaller VMC, then study how it works and build a much much larger gantry machine. I can understand how moving the parts and resetting could cause errors. One day I want to be able to machine up to 7 mtrs in length, not sure on the width just yet, maybe 3 mtrs. So many projects.. I will get their eventually.

they make much bigger machines than that so it's doable. seems like the huge gantry machines have a fixed gantry and the table moves. those kinds of designs take up a lot of floor space though. 5' by 10' moving gantry is probably as big as you want tot go with a moving gantry style. moving gantry machines are hard to keep rigid and the high the gantry the worse it gets so if you need the height a fixed gantry is probably the way you need to go.

I would like to be able to machine linear rails flat after they have been welded.

If I have to I could buy a block of land and build a decent sized shed to put it in. Would need to work out a way to make money from it regularly tho. I am sure if I added enough steel I could make it pretty rigid.

What precision are you aiming for?
If u just want to get staight rails:
I think u could run a milling device that is controlling its "hight versus part" only by measuring a laser beam parallel to the part.
Mike

depends on the design of the frame too. if you want side mounted rails then you probably want a 5 axis with the cutting head that can rotate and pivot so you can do the entire table in on shot. that's how you get high precision and true squareness. this is a whole new level of build. if you want to build them fast this is the way to go. i bolted everything together on mine so i had some control over datum points. this was the only way to keep things straight and square with a small milling machine. and it took forever with a manual mill

literally on the other side of the country from me looks like a start up from the website not to much information. but that design is pretty common with the home shop builders.

machinedude wrote:

depends on the design of the frame too. if you want side mounted rails then you probably want a 5 axis with the cutting head that can rotate and pivot so you can do the entire table in on shot. that's how you get high precision and true squareness. this is a whole new level of build. if you want to build them fast this is the way to go. i bolted everything together on mine so i had some control over datum points. this was the only way to keep things straight and square with a small milling machine. and it took forever with a manual mill

Yeah that would be the goal. I would also like to machine the side rails flat on a plasma table after welding so a rotating head would definantly be needed.

even just having enough travel to do operations in one shot id a huge step in speeding the process up.if you think modular in design you can work on interlocking sections, you just have to have really good datum points to work from to do it this way.

when you start splitting hairs you have to do lots of extra stuff to make it happen. any kind of item that has been welded should be stress relieved after. machining will making it closer but what happens is as you cut the part moves from internal stresses from being welded. the same way you welders will tack around the parts to keep things from moving to much could be compared to machining a part that has not be stress relieved by taking light cuts and creeping up on sizes.but the same problems are there, you manage the movement by reducing it a lot but you still have small amounts of bow and twist.

the way you hold your work matters too. if you are working the bow from something you have to go about it the right way. usually your first cuts are in a way the keeps the piece in a free state. once it's flat in a free state you can pull it down with clamps or hit the part down in a vise.

fun stuff when you start to work on closer stuff yet you cross over to the next level and get into surface grinding that end of the of the trade tends to make you crazy if you stick around to long