New Machine Build- Questions on various plans available

[Grumple]

Hi, This is my first post here. I am gradually getting my workshop the way I want it and was looking to buy a plasma cnc table. The after checking with all the usual vendor options, I had to ask why are they so expensive? So I did some reading on building my own and arrived here many times. I just want a small 4x4 table and have looked at many build threads and they all seem to take a different approach. So, to make my research more focused, what is the best design on a 4x4 table? I plan on using Mach 3 and have all the computers I need, and I want THC for sure. How many available FREE plans are available so that I can download and evaluate them? I plan on buying a mill before I start the project and already have welders etc....
Thanks for your time,
G

[Grumple]

Let me rephrase that... What type of rails are easy to build but accurate. What is better, servo or stepper? Belt, chain, or rack and pinion?
Thanks,
G

[DanOSB]

for electronics part i suggest you buy the complete kit from candcnc.com

for stepper and servo it depends on what your needs are.. the stepper works really well but doesnt have feedback so it doesnt know the actual exact postion.. incase the stepper motor gets jammed or miss step u might loose a little accuracy..

one of my machine is servo and other is stepper.. so far that stepper machine works perfect i havent had problem only time i had problem is when the machine required to pause and it lost the step so i homed it and that solved the problem..

cost of stepper/servo is big difference

for linear rail i suggest you use v bearing with v railing if i had to build whole thing again i would use that instead of pillow block open bearing that is currently on my machine..

for gearing part.. one of my machine is on chain drive and the accuracy is very good.. im happy with it..

the rack n pinion is a good way to set it up.. but for the cost factor chain is very cheap..

hope those info helps

Cheers
Dan

[Dustin407]

Well their are many different aspects to consider on a cnc build. First thing is what is your total budget on a 4x4 table. Also, when do you wanna have your machine up and running? This will help get you going in the right track. Some people spend 3 thousand dollars and others spend 12 thousand. If you have a very low budget you have to cut corners on your rails/material size/cnc package etc.... Some very cheap tables cut just as good as a very expensive table, all depends on your decision making on the design/materials. Second what is your objective of the parts you cut, artwork, signs, close tolerance parts? If you cut artsy stuff you dont need to be as accurate therefore your table can be built cheaper and cut corners. I agree 100% with what DanOSBh and his suggestions. Good setup is stepper package from candcnc w/ thc(geared 4.5,5:1), simple waterbed, v-rail on one side, roller bearings on the other, rack/pinion xy axis, acme/ballscrew for your z, very light gantry for better acceleration and braking(alum.). This may help....

[millman52]

Originally Posted by Grumple Hi, This is my first post here. I am gradually getting my workshop the way I want it and was looking to buy a plasma cnc table. The after checking with all the usual vendor options, I had to ask why are they so expensive? So I did some reading on building my own and arrived here many times. I just want a small 4x4 table and have looked at many build threads and they all seem to take a different approach. So, to make my research more focused, what is the best design on a 4x4 table? I plan on using Mach 3 and have all the computers I need, and I want THC for sure. How many available FREE plans are available so that I can download and evaluate them? I plan on buying a mill before I start the project and already have welders etc.... Thanks for your time, G

If you are anything like me there isn't a set of plans out there I'd follow to the letter. If you change much of anything on a set of plans. You then are forced to do other work arounds as well. So if you are going to re-invent the wheel so to speak. Just as well start from scratch with borrowed designs from other factory level & home built modles.

Besided I don't personally know of more than a couple sets of table plans anyway.. 1 set is listed here in the build logs for free. Last time I was on ebay someone is selling plans for about $19.99 I think


If you'll take all your free time for a couple weeks & read I DID SAY READ NOT SKIM the build logs in both plasma tables, & router tables sections of CNC Zone You'll have a pretty good knowledge of what is involved & pretty good look at most design variables.

If you have the ability to build one of these tables. Not having a set of packaged plans shouldn't be a problem either.

NEIL

[Grumple]

Originally Posted by DanOSB for electronics part i suggest you buy the complete kit from candcnc.com for stepper and servo it depends on what your needs are.. the stepper works really well but doesnt have feedback so it doesnt know the actual exact postion.. incase the stepper motor gets jammed or miss step u might loose a little accuracy.. one of my machine is servo and other is stepper.. so far that stepper machine works perfect i havent had problem only time i had problem is when the machine required to pause and it lost the step so i homed it and that solved the problem.. cost of stepper/servo is big difference for linear rail i suggest you use v bearing with v railing if i had to build whole thing again i would use that instead of pillow block open bearing that is currently on my machine.. for gearing part.. one of my machine is on chain drive and the accuracy is very good.. im happy with it.. the rack n pinion is a good way to set it up.. but for the cost factor chain is very cheap.. hope those info helps Cheers Dan

Dan,
Thanks. That is the kind of info I was after. I had already found the CandCNC site. I will want to put the machine on casters so I can roll it outside of the shop into the driveway to keep the dust down. I already know about the water table but have seen many pics of machines outside. They must be there for a reason.

Grumple

[Grumple]

Originally Posted by Dustin407 Well their are many different aspects to consider on a cnc build. First thing is what is your total budget on a 4x4 table. Also, when do you wanna have your machine up and running? This will help get you going in the right track. Some people spend 3 thousand dollars and others spend 12 thousand. If you have a very low budget you have to cut corners on your rails/material size/cnc package etc.... Some very cheap tables cut just as good as a very expensive table, all depends on your decision making on the design/materials. Second what is your objective of the parts you cut, artwork, signs, close tolerance parts? If you cut artsy stuff you dont need to be as accurate therefore your table can be built cheaper and cut corners. I agree 100% with what DanOSBh and his suggestions. Good setup is stepper package from candcnc w/ thc(geared 4.5,5:1), simple waterbed, v-rail on one side, roller bearings on the other, rack/pinion xy axis, acme/ballscrew for your z, very light gantry for better acceleration and braking(alum.). This may help....

Dustin,
I was thinking $5,000-$6,000 would do a fine machine. Some of the commercial ones look cheap although I am sure they work well. I will most likely use a PowerMax 45. I want THC for cutting thin stuff too. I would most likely want to do the artwork stuff along with 1/2 steel. Also 1/2" aluminum. I want it to be versatile. Mainly brackets and gussets etc... I want to use Mach 3 and Sheetcam. Good point on the gantry. I would have not thought a heavier steel gantry would slow it down. As long as its reasonably fast its good enough as its a home workshop and not high production.
Thanks,
Grumple

[Grumple]

Originally Posted by millman52 If you are anything like me there isn't a set of plans out there I'd follow to the letter. If you change much of anything on a set of plans. You then are forced to do other work arounds as well. So if you are going to re-invent the wheel so to speak. Just as well start from scratch with borrowed designs from other factory level & home built models. Besided I don't personally know of more than a couple sets of table plans anyway.. 1 set is listed here in the build logs for free. Last time I was on ebay someone is selling plans for about $19.99 I think If you'll take all your free time for a couple weeks & read I DID SAY READ NOT SKIM the build logs in both plasma tables, & router tables sections of CNC Zone You'll have a pretty good knowledge of what is involved & pretty good look at most design variables. If you have the ability to build one of these tables. Not having a set of packaged plans shouldn't be a problem either. NEIL

Neil,
I found those plans from MLaws and thats all I got to go with. They look like a great start. The questions a new builder like me have are sometimes really basic like, on a 4x4 table is it really 4x4 or and inch larger for clearance? Hate to find that out after its done. I have thoroughly read a lot of builds. Some of them leave you hanging where the OP says he will report back and never does. Others give you part of the plans but not all of the plans. I am a good reader. I need to read some in the CNC Router area though.
Thanks,
Grumple

[DanOSB]

One suggestion i have... try build a table with water bed.. the results are amazing.. at first i was expecting far less improvement from water bed and now only dust that comes out is steam which is nothing compared to before when i did test cuts without water bed holly cow the dust got everywhere and my whole shop is dirty fast

if u have waterbed u wouldnt even need to pull the machine outside to cut

[DanOSB]

i would build at least 2 inches larger than 4x4 so make it 50 inch by 50 inch

[Grumple]

Originally Posted by DanOSB i would build at least 2 inches larger than 4x4 so make it 50 inch by 50 inch

Dan,
Thanks for the clearance answer. I know about water tables but they seem like they too would be messy. I guess I will leave that option open. can a water table be low capacity like 1 or 2" of water and still perform properly? I would hate to move the machine and slosh all the water on the floor.
Thanks,
Grumple

[millman52]

I's say that 2" is a minimum measurment on extra room. I guess it depends some on the material you are planning to cut. If it's all thinner material like gauge thickness materials less toom is needed because the material is easy to handle. Once you get into thicker material & have to use an overhead hoist or fork lift to handle material. Parts of your machine become much more vulnerable to being hit by swinging sheet metal.

The direction you gantry traveles along 2 of your table frame rails needs to be long enough to park your gantry completely clear of your cutting surface. I would expect to obtain a cutting surface of 4' X 4'. Your frame size will approach 5' X 6' outside dimentions. My 5' X 10' cutting surface is actually 6' 4" X 12' 4" outside dimentions.