Smithy 1240 cnc questions

[nupeswv]

I am looking at buying a smithy 1240 cnc mill and have a couple questions. It will most likely be the full package with their controller as money is not a big issue.

-Will it work alright with Mastercam ? Mastercam does have Fanuc posts but I am not sure if they are right for this controller. (It is the software I am familiar with). What type of Cad are others using with success?

- Do people have alot of problems with stepper motors as opposed to servos? I plan on making a fair amount of parts off of jigs.

_ Is there alot involved in getting one up and running after shipment? I am fairly knowledgeble in mechanics and have done machining for 20+ years.

- Has anyone gotten one of their new 1240's with the belt drive and had the option of getting servos instead of steppers? I believe they had an older model with servos once.

Thanks in advance for any response to this.

[LUCKY13]

I dont think anyone has bought this new machine yet. But you might find someone that will know the anwsers to the softwear question. Might be better to call Smithy up & ask them the question on the softwear capatibility.

I am afraid this setup is just to new for many to know much about it. Although there was a few that had bought to older machine. But there has been alot of changes made to the machine ( needed ones & some not so much). Like the new belt drive with VFD is a big improvment over the older gear headed machine ( or atleast should be). But droping the servos over stepper IMO was not a good thing, although steppers are nothing to be worried with, most machines do use them, unless its a factory CNC machine.


Jess

[jmg]

Hi Nupeswv,

Smithycnc 1240 claims 1700 oz-in steppers for xyz.

For a comparison, Tormach PCNC is 640 oz-in for xy and 1200 oz-in for z. Tormach claims the 1.5 hp spindle will stall, or the cutter will break before steps are lost.

I think both machines are pretty good, lots of videos at Tormach site, only one that I know of for Smithycnc 1240, however the machine is newer so they probably need time to post.

Tormach has ground ballscrews at P4, whereas, Smithycnc is P5 (are we going to grumble about .0003" difference? --a few of degrees of room temperature difference may negate .0003" anyway!!)

Again, I believe both machines are worthy of purchase.

Let us know what you decide on, we'd appreciate hearing how it goes for you!

jmg

[philbur]

The practical difference between the two is that with servos (closed loop)you can set your maximum feed rate closer to the limit of the system with less worry about lost steps. With steppers (open loop) you have to back off a bit on the maximum allowable feed rate in order to avoid the risk of lost steps and the ensuing crash. If maximum feed rate is of commercial value to you then go with closed loop. If it isn't a big issue then save some money and complication and go with open loop.

My opinion is that if you think you need a closed loop system then you probably need a fully fledged "commercial" machining center.

Just some thoughts from a novice.

Phil

Originally Posted by nupeswv I am looking at buying a smithy 1240 cnc mill and have a couple questions. It will most likely be the full package with their controller as money is not a big issue. -Will it work alright with Mastercam ? Mastercam does have Fanuc posts but I am not sure if they are right for this controller. (It is the software I am familiar with). What type of Cad are others using with success? - Do people have alot of problems with stepper motors as opposed to servos? I plan on making a fair amount of parts off of jigs. _ Is there alot involved in getting one up and running after shipment? I am fairly knowledgeble in mechanics and have done machining for 20+ years. - Has anyone gotten one of their new 1240's with the belt drive and had the option of getting servos instead of steppers? I believe they had an older model with servos once. Thanks in advance for any response to this.

[dmichals]

I purchased the Smithy 1240 mill four months ago, so far it has been a good machine, I have been using mastercam to cut parts and so far it has worked fine. No problems with the stepper motors. I have had trouble with the X and Y travel proximity switches, in fact I am waiting on a replacement for the third failure now. Otherwise no other maor issues.

[GSSTUART]

Hi - I got my 1240 Smithy mill in early Feb. and have been using it regularly since. I am a machine designer/prototyper and use it to make parts for the manufacturing machines I make. I have done UNMW (40 hrs.), 6061 aluminum ( 50 hrs.), and low carbon steel (20 hrs). The 1240 performs well once I figured out what it could handle. For the aluminum I was using a 1.25 in. diameter 3 flute cutter with al. inserts for a lot of material removal. 3000 rpm, 15 ipm, 0.080 doc. The inverter driven 3 phase motor works well but under heavy load the spline clearances on the spindle shaft seem to contribute to some chatter. The belt drive is a blessing. I use Mach 3 and have found that when I increase the feedrate during machining the rapid feedrate is increase by the same percentage. I have crashed a few times because it lost steps being unable to move at 2X the standard 75 ipm rapid. The big stepper motors seem to be able to do anything I have asked it to do without a problem so far. I did break a 3/8" cutter one time by driving it (spindle off) into my material, the X axis stepper didn't even seem to notice. I have done some holding jigs that were 24" X 24" by revolving them about a fixed center reference pin. They turned out nicely so I am quite pleased with limits of the machine. Whenever I have needed to call Smithy there has been a person there to talk to and they have answered my question well. As far as setting the unit up the biggest challenge for me was unloading that much weight out of my Sprinter van and then lifting it up so I could slide the Smithy stand under it in my low ceilinged shop. Both tasks were accomplished with a chain hoist and a little creative rigging. There is little or no mechanical challenge involved in the uncrating and setup.
I use IronCad, Dolphin CAD/CAM (it has an IronCad addon that quickly send surfaces to the Cam software), CutViewer ( for cnc verification) and Mach 3 for machine control so I can't comment on you software questions.
So far I feel like I spent my money wisely and feel very good about having the Smithy.

Good Luck
Gary

[bones]

Hi Guys,
I have been a bit worried about the purchase I got my boss in the US to do on a Smithy CNC 1240.
Other than hardly any information on the net about them. Hardly anything on their site.
And not a great deal of replys to emails.

It makes me feel a bit better that you guys like your machine.

Do you guys have any information on connecting the unit to the PC.
eg Confirgurations etc.

And any recomendations on setting up.

I'd love to see some of the work you guys have done on the machine.
Do you have any pictures at all?

I'll be flying over to the US in a couple of weeks to set the unit up.
Any help would be great.

Cheers
Rodney

[benji2505]

The units come with some setup info, but you should be able to get them at Smithy as a pdf file upfront. The units are heavy.

If I was in your position I would check the following parameters first: 1.angle between table and spindle in x and y direction. Do this with a dial indicator. 2.accuracy of the table and spindle movement. Do this with dial indicator and reference pieces. 3.adjust the physical reference pieces. The work cube set up in China might be far less than the machine has to offer. 4. Control functions incl. cooling.

Hope that helps

[bones]

Hi benji2505,
Thanks for the info. I finally got the info I need from Smithy.
They are suppose to dial the machine in before you get it.
But I will check it all out. Ta.

Rod

[fastlanecafe]

DMICHALS AND GSTUART,
I'm thinking of stepping up to a larger mill- What type of spindle drive does the 12-40 have- is it installed in USA or China?
How about the CNC- USA or China?
Any opinions on the reliability of them?
Thanks

[GSSTUART]

I like the spindle drive design on the 120. Its a 3 ph. motor directly driving the spindle using a toothed belt. The spindle itself easily drops out of the head by removing 3 screws. I took it out once and it appears substantial enough for the job and would be fairly simple to rebuild or ship back to Smithy to have them rebuild. The upper end of the spindle shaft is a spline and on my machine the clearance between this spline and the drive pulley it engages is greater than I would like. I can grab the milling cutter and rotate it back and forth and feel the spline moving in the pulley. I was having problems with chatter when using a 1.25" cutter (on aluminum) and I had to reduce feed and DOC to compensate. I have since stopped using the R8-ER40 collet adapter I was using for heavy cutting because the collet adapter extended the cutting tool almost 3" beyond the end of the spindle. I think that additional distance was causing a lot of flex at the cutter end. I now use 1-1/2", and 2" cutters with R8 shafts and the operation is much more rigid. I liked the ER40 collet because bit changes were quicker but for the heavy cutting it didn't pan out. All in all I am still happy with the machine. I have attached a few pictures (If I can get them loaded) to show some of what I have been doing. The black material is 3/4" thick UHMW and the others are of some Aluminum assembly jigs I made.
PS. Upload is not working right now. Will persist.

[fastlanecafe]

Thanks-
Is it USA or Chinese motor- I am pretty good at fixing anything mechanical that could go wrong, but 3 phase VFD is out of my league, so i would want to know its good stuff. On my 3 in 1 machine I have about 0.008" lash in the spline shaft which is expected for a low cost unit. Its ok with small end mills, but you can feel the lash when you use a fly cutter. Its odd that an expensive CNC machine would have that issue too.