Looking to upgrade hardware

[cnc4me]

Thanks Martin54, I presume you are referring to the weight of the spindle causing my z axis to deflect? I had not given much thought about the weight of the spindle. My original thoughts were to go with a 1.6-2.2kw spindle.
Multiple flutes are good thought as well. I bought a 1/4" three flute endmill the other day so I will experiment with that.
Andy

[martin54]

Depends what sort of feed rates you can achieve, you still have to make sure you have the correct chip load per flute, to be honest the majority of my bits are single flute mainly due to materials I cut & the speed the machine is capable of safely running at.

I was actually thinking about a combination of things as far as your machine goes, weight of spindle plus the length of the z axis & it also looks to be quite narrow. Did you build the machine from a set of plans that you bought? What's the construction ? Ally, steel ? See that you have a wooden frame but guessing it is braced with something else.

[hdtheater]

I use single straight flutes and up cut two flute spirals mainly. I use a Bosch Colt as my router.

[cnc4me]

The machine is made of extruded aluminum and solid 5/8" (approx) aluminum for the gantry. It is a kit from XYZgantry.com. The machine sits on top of a wooden base I built. Verrrrrry solid. :0)
Its not a shop bot but it should do. I just have to learn the limits of thge machine.

[martin54]

The machine is made of extruded aluminum and solid 5/8" (approx) aluminum for the gantry. It is a kit from XYZgantry.com. The machine sits on top of a wooden base I built. Verrrrrry solid. :0)
Its not a shop bot but it should do. I just have to learn the limits of thge machine.

Doesn't matter what it is as long as it does what you want it to, my machine isn't the best in the world but it does what I need it to. I was going to build a machine from scratch but then an old broken machine came along at a good price so I ended up just converting the electronics in that. Learning the machines limits is the fun part lol
I only commented because you seemed to have a very high gantry.

[swaggs21]

I have a highly, highly modified Joe's CNC that can run 2500 ipm rapids on X and Y, and 750 ipm rapids on the Z. I don't run it that fast because it is too fast for me to react to anything. Even at 1000 ipm (what it is currently set at), I don't have time to react, I just feel more comfortable with it :p

To me, it isn't about what machine you pick since almost all of them run on the same X,Y,Z gantry. It is the components used.

If you are going to run fast and have great quality, linear rails are the only way to go. You could have a infinity long debate on lead screws versus rack and pinion or steppers versus servos, but it really comes down to budget. Can you afford lead screws that will run 2500ipm and servos to give you the quality of a Thermwood, then go for it. If not, rack and pinion with steppers and digital drives are a great option.

One thing I will never compromise on again is linear rails. They might be expensive, but are worth every single penny in my book. I have never had someone come into my shop to look at the machine that has walked away saying that would rather keep linear system X on their machine.

[hdtheater]

Now you have me thinking.

So, when a company rates their machine, is it a matter of all the components working together and the rate it based on dependable quality? I wonder if I could tweak the one I have to get get faster cuts.

I would like the bigger X,Y,Z. However, if I could get better speeds to of what I have then I could prolong the purchase of the bigger one.

The way I look at it, when it comes time to buy the next CNC, I go for size and speed. My only real need now is speed.

If I looked at tweaking, where would I start? Making it less flexible? Faster motors?

-Eric

[swaggs21]

I don't know what type of linear motion yours currently uses (it looks like V-Bearings), but you have to make it more rigid before you make it faster.

Switching from V-Bearings to linear rail will make a massive difference in cut quality, and may give you some upgrades in speed as well due to less friction.

[martin54]

I don't know what type of linear motion yours currently uses (it looks like V-Bearings), but you have to make it more rigid before you make it faster.

Switching from V-Bearings to linear rail will make a massive difference in cut quality, and may give you some upgrades in speed as well due to less friction.

Think you are looking at the wrong picture, the original poster is running a shark, had a look at the website & it is on round rail which looks to be unsupported although it was difficult to tell from the picture I found so could be supported.

The website claims that your machine will run at 200ipm which is double what you seem to be maxing out at just now so there should be a lot of room for improvement. without spending lots of money upgrading this machine.

[PaulRowntree]

Switching from V-Bearings to linear rail will make a massive difference in cut quality, and may give you some upgrades in speed as well due to less friction.

Interesting. Although I would agree that good linear profile rail is probably the best, I see that Ahren (cncrouterparts) is using V-rollers on his 'pro' equipment. I suppose this means V-rollers are better than his 'std' line of skate-bearing trucks on flat CRS, which were pretty good to start with.

[hdtheater]

I m going to show my ignorance a bit. When you say linear rails are you referring to what the gantry travels on for X,Y, and Z axis? I have round bars that have bearings that glide over them. Here is a pic showing what I am talking about:



This is the Z axis. The X is built the same way, but the Y has a longer bearing that is about 2-3" long.

-Eric

[PaulRowntree]

What I meant was square-ish rails that have trucks that move along the long axis. Profile rails have grooves running along them that constrain the truck to remain flat even when torqued; round rails like you have cannot prevent the rotation.

This is Thomson's approach : http://www.thomsonlinear.com/website/co ... lerail.php

[hdtheater]

Thanks Paul, those are far more sophisticated than what I have.

[hdtheater]

Think you are looking at the wrong picture, the original poster is running a shark, had a look at the website & it is on round rail which looks to be unsupported although it was difficult to tell from the picture I found so could be supported.

The website claims that your machine will run at 200ipm which is double what you seem to be maxing out at just now so there should be a lot of room for improvement. without spending lots of money upgrading this machine.

The x axis not supported. However, the Y axis is. I can run it at 200ipm, but the quality starts to suffer at that rate.

I have replaced some of the plastic parts as they broke with aluminum to try and stiffen the machine up a bit.

-Eric

[PaulRowntree]

Thanks Paul, those are far more sophisticated than what I have.

More sophisticated than what I have as well, to be sure! I am running skate bearings on inverted Al Angle on X and Y, and on the edges of Al angle for Z. Not the best, but the best I could wrap my head around at the time. The Al wears a bit, then settles down. I am hoping to move to V-bearings on ground angle steel, like the mechmate and Joe's hybrid use.