[BLarks]

Hi guys, basically my first post here and really wasn't sure where to put this thread so I'm hoping this was the best place. I'm new to cnc, I do have a little manual lathe and milling experience. I have been researching as much as possible but I cannot seem to find specific answers to my questions, although some questions may have been answered elsewhere, I thought it better for myself to ask here. I am looking at a small machine and I know quite a few people will say stay away from the 3040 size machines, but I really don't need anything bigger at least for now but mostly I can't really afford a 6040.

Now I have been trying to find a definitive review or similar about the stepcraft systems, I am looking at the 420, the alternative is the omio x4-800l. Pros for the stepcraft are I can get it here in Australia which means, local support for any problems, no import duty which will be a killer for the omio. The stepcraft seems to have mostly what I need, in particular I like the bath for cutting carbon fiber, and other various add on bits for possible future use. Main use is purely hobbyist and cutting carbon and alloy. At the moment the stepcraft seems to be what I'm leaning towards but I'm posting here to see if you guys can either talk me out of it or say yes go for it.

Youtube videos show this machine to do what I need just fine, but maybe someone can confirm from personal experience or greater knowledge than me if the stepcraft will be suitable compared to something like the omio or similar. Now as far as the spindle I see that the kress 800 seems to suffice for what I need and even seen the proxxon cutting alloy, the question is should I go for a different spindle setup such as a brushless with vfd? On that note I notice the clamp is 43mm diameter is there a brushless spindle setup that will fit, the stepcraft hf-500 spindle seems pricey.

Ok will leave it there for now as the post is becoming quite big

[Fastest1]

I am not familiar with the machines themselves though I did just check out the 420 on the Stepcraft site. It looks like a decent little machine however this part of the market is pretty saturated. Small machines that are reasonably well done shouldnt be hard to find. On the other hand, it isnt a project it is ready to go. For some that last part is key. Usually we all scream bigger is better. It of course isnt always the case. I think it is better to get started.
If it meets your needs at this time, will do what you want and be within your budget, what is the hold up. Go support the local economy and learn something along the way. If you need a bigger machine later, you will have 2 machines then ;-)

[BLarks]

Hey thanks for the reply Fastest1, I was looking at some ebay machines last night and it seems very difficult to find a machine from a seller who has anything even close to 100% feedback which scares me away from buying off them and to be honest I really don't want to be dealing with someone from china etc who have poor or no customer service whatsoever, I have no idea what customer support is like from stepcraft but at least they have an Australian distributor. Although, don't get me wrong I purchase from overseas more often than I buy locally purely because I get better customer service from those places, but I think for something like the cnc buying locally will certainly help in regards to shipping and returning anything for repair or warranty.

The stepcraft machines do come unassembled which I don't mind as I would prefer to build it as that is part of the experience for me. I think unless someone posts here giving valid reasons not to get the stepcraft I think it will be the direction I go in. As far as spindles go should I get the kress 800 or is it recommended to go for a brushless setup, assuming there is something available that will fit?

[Fastest1]

What type of controller and software do you intend to run. Wasnt it available with Mach or UCNC?

[BLarks]

To be honest I hadn't got that far yet. For an extra price you can add uccnc and a uc100. From my understanding I could use a usb connection to a pc with mach 3 as the controller, is this correct? I have AutoCAD, I assume i will need CAM software as well.

Edit, ok further reading suggests that mach3 won't work with usb but needs an adapter such as the uc100

[Fastest1]

Mach 3 can work with either USB or Ethernet Smoothstepper. Similar to the UC100. However UCNC provides its own motion control software. I have seen a few examples of UCNC in direct comparison to Mach running supposedly the same GCode, the results of the UCNC on this particular project looked much better. I have no experience with UCNC though.
Since you are just starting out I would suggest the UC package. In the end the price will be about the same a copy of Mach 3 and a USB or Ethernet device. You will be getting away from the dreaded parallel port which isnt being supported in modern OS's anyway. Just make sure that no functionality of Mach or UCNC is lost due to type of connection and that if there is a loss, can you do without it? For example I was using a Ethernet Smoothstepper on my lathe. 2 functions were not available, one was diameter. The lathe would only operate in radius function. I can live with it but why, I think in diameter. Btw running Mach under the parallel port allowed either choice. There was another function lost but I cant remember what it was at this moment but I didnt like being without it which prompted my looking into LinuxCNC.

[BLarks]

Hey thanks Fastest1, I tend to agree with you and after many hours of reading last night I decided that I will go the uccnc/uc100 route. I have emailed stepcraft asking about what the base setup comes with IE parallel or usb port just to confirm as there seems there is 2 options available. Also I think I will go with the kress 800 for now unless my research uncovers a better option for the spindle, reading about the stepcraft spindle option revealed a few disappointed people, not to mention its nearly $1000aud. I could most probably get a cheaper machine setup from ebay but it seems all machines have their pros and cons and feel the stepcraft option is best, unless I discover another option.

[Fastest1]

I hear of Kress quite a bit, nothing negative per se but have no personal experience with them. The real thing is, will you get to build the parts you want soon? If yes, then it is worth it.

[BLarks]

Same here Fastest, from what I have read the kress seems more than adequate and a good little unit. I have been in contact with the sales rep for stepcraft here and he seems like a really nice fellow, very helpful, of course they all are I guess when they want your business but he seems genuine so I am confident in buying from him and in saying that I have placed an order for a machine. He has thrown in about $70 worth of cutters ( which is probably only a couple) and will ship it for free, overall fairly happy with the deal. Machine will take a few weeks to arrive as he is out of stock and is waiting on orders from the manufacturer, fine by me as I'm in no rush and it gives me a little time to recoup some money and have a look at software etc.

[BLarks]

Well I got everything assembled and have homed all axis. Very happy with the stepcraft machine so far, of course I have not machined anything yet but happy with the package.

[Fastest1]

Great! Have you cut any air yet? Just to watch it under computer control.

[BLarks]

Sure have, jogged it around, up and down. I'm hoping to maybe try and cut something over the weekend, time permitting and providing I am confident in creating something simple in cad then into cam.

[Fastest1]

Does it have homing switches?

Does the UCNC software come with a sample program? Mach has a Roadrunner (the bird not car) that is generally the first thing people cut. Why a Roadrunner, I have no idea.

[Fastest1]

Here is a series of GCodes that could be used. Demo Gcode

Check for the comments on size of project. Verify it will fit within the parameters of your machine, keep your Z above your work the first run, just to verify. Hit start and watch in amazement. Then you will be hooked.

[BLarks]

Does it have homing switches?

Does the UCNC software come with a sample program? Mach has a Roadrunner (the bird not car) that is generally the first thing people cut. Why a Roadrunner, I have no idea.

I think so, there are switches that alert the controller that it has reached its end travel on all axis, are these the same as home switches?

I haven't had time during the week to have a look to far into uccnc but it would be nice if it did have a sample. I will look more over the weekend. Thanks for the link to the demo gcode Fastest I will certainly check it out. I will get some mdf or something to practice on. I work at a school so I have been scouting their off cut bins for something but as it is school holidays it seems they have already cleaned up.

[awerby]

The ones that tell the computer when the end of travel has been reached are called limit switches. Home switches can be different, or you can use the limit switches to find home. But each linear axis only needs one home switch; it needs two limit switches.

[BLarks]

Thanks awerby, thats what I thought that they were just limit switches but needed clarification, I was reading about home switches before Fastest had posted about them hence the question. Actually the stepcraft machine has only 1 limit switch per axis, I believe only 1 per axis is needed because when installing uccnc I had to select what machine I was using so it must have entered machine travel dimensions. It does know when the limit is reached when hitting the opposite end of where the limit switch is. Is it recommended that I look into getting home switches?

[109jb]

A couple things.

1-You don't need 2 limit switches per axis. There are a few different combinations that make this possible.
. A- Many installations use a single switch that can be tripped at either end of the travel. One example is a mechanical switch in the center with a cam at either end that trips the switch.
. B- Software limits can be used to prevent exceeding the machine travel. This option can even be used on some control software without any switches installed, but most commonly this is used with a home switch. The home witch allows the control software to detect where the home position is and then from there it can use software limits, or actual limit switches, or a combination of both. For example I set my machine up with one switch on each axis. The switch acts as a home switch for homing, and then as a limit switch for one end of the travel of he axis. The other end of the axis travel is handled by software limits.

2- A switch can be configured to do double duty as both a home switch and a limit switch, thereby reducing wiring and hardware requirements.

I am not sure how your particular machine is set up. You would have to examine how your switches work, what triggers them, etc. Then the control software setup would also need to be checked to see how it is set up.

[BLarks]

Hey 109jb, not sure exactly how it works but the machine has 1 switch per axis, when I installed uccnc I had to install software from stepcraft which loaded machine parameters (I assume) into uccnc. So I assume where the switches are installed is to mechanically define end of travel and the software controls the opposite end limit. So can the switches I have also be used as home switches?

[109jb]

Hey 109jb, not sure exactly how it works but the machine has 1 switch per axis, when I installed uccnc I had to install software from stepcraft which loaded machine parameters (I assume) into uccnc. So I assume where the switches are installed is to mechanically define end of travel and the software controls the opposite end limit. So can the switches I have also be used as home switches?

Yes they can. I have my switches set up with one per axis. Take my X axis for example. The switch triggers about 0.1" from where the axis would mechanically crash. This gives a little room to decelerate and stop if for some reason there is a runaway. When homing, the axis approaches the switch at a moderate speed and when the switch triggers the software knows it is at the switch. In my case I have the home position set to be an additional 0.1" from where the switch triggers, so the software backs off that 0.1" (0.2" from the mechanical limit), and assigns this as the home position for that axis.

When a switch is operating as a limit, and gets triggered, the software should disable the motor drivers and put the machine in an alarm state. This is all handled by the control software and is how most hobby machines are set up.

When Homing, the switch triggers, but the homing routine allows it without disabling the motors or going into alarm, in essence disabling the switch as a limit and enabling it as a home switch. If it didn't do this, the switch would trigger, the motors would shut down, and the software would go into alarm state. So, it is a special use case and is dependent on the software used. I use LinuxCNC, but most programs these days can use one switch for both limit and home switches.

This next part doesn't have to do with your question, but I feel like mentioning it.

Most hobby machines have the limit switches connected exclusively to the software that is controlling the machine. This works fine most of the time, but a true limit safety switch system should be independent of the software. For example, when the switch is talking to software, you are relying on the software to perform the correct action when it senses the trigger of the switch. Again, this works most of the time. However, what if the software is having problems and is what caused the runaway in the first place. Now you are relying on a problematic software to stop itself. A true safety limit would trigger independent of the software and shut everything down regardless of what a wonky program is doing. Having said that, my machine is not set up that way. Why? Well I know that crashing into the mechanical stops on my machine will not really damage anything because of the size of the machine, torque of the axis drive motors, etc.However, if I had a larger more powerful machine, or a servo driven machine, I would install an independent safety limit switch system. If you did this you would need switches to trigger at each end of the travel and a separate home switch. The Cincinnati VMC's I used to run had an independent system and if tripped would disable the motors and also signal the controller of the fault, but you couldn't just power the machine off the switch and there was no override for a over-travel limit. You had to manually turn the feed screw with a wrench to move the axis off of the switch before re-starting the machine.