Hello All, Hoping to get some help here. I'm considering purchasing a C-Beam design. I've been exploring the web for over a week now and this is what I'm leaning towards. But then again there's so much information you quickly become overloaded. There is one question that I haven't found an answer to and thought maybe the more experienced folks here might have an opinion. Which is better the standard gantry's that move in all 3 axis or the C-Beam design where the table moves and the gantry is fixed? ------------------------------------------------------------------------------------------------------------------------ Initially what I planning to work with - Wood, Plastics, Foam, and maybe at some point aluminum. Later plan "B", if you can call it that , is to add a laser. I'll use this etch/cut wood and etch glass. Further down the road (Plan "C") I hope to add a Z-axis to do circular objects (Glass). Here's a list of what my initial funding can get me. Openbuilds C-Beam Frame Openbuilds Controller 24V Power Supply Nema 23 High Torque Stepper Motors Any help is appreciated. I just don't want to find out later that there is something I should have considered. Ed
It's not quite as simple as that. In theory both have their strengths. Unfortunately, the C-beam itself has a couple weaknesses that tip the balance toward fixed bed systems. The main problem is the bed is only supported in the center region. When the cutting tool is near the edges it can cause flex in the bed thus affecting the cut. The other issue is that it's an old design and was created before some of the current parts came online. The X and Z gantries are not as stiff as they could be because they use older model plates. All of these issues are easily correctable by the end user but it adds about $150 to the cost of the system. Assuming all things being equal with the strength of the systems though, there is one specific advantage to the fixed bed systems, you can cut material longer than the bed of the machine. You can easily carve a 6' board on a 500mm bed using a system called tiling (or pin registration). Handy if you find the 13" usable Y-axis length of the smaller systems limiting. If I've convinced you to that going over to a fixed bed system is something worth considering but don't want to drop the additional $600 to upgrade to the Sphinx 55 and if you can wait a week or so I'm about finished with a fixed bed system that'll split the difference on the cost of the two systems mentioned (totaling out at $1225) and offer a true build area of 11"x13"x3.75".
Rick, Thanks for thr reply. I didn’t even consider that there would be deflection. That could be fixed by using 2 acme screws under the table. But you’re right I’d have to add that extra cost in. I’m interested in the build you’re currently working on. Got a BOM and cost breakdown? I’d like to see if I can work it into the budget. You can email me if that’s easier. Thanks again, I think you may have saved me a lot of trouble.
