Introduction and design help.

Good Afternoon all;

My name is Larry Alexander and for years I have been interested in CNC. I live on the island of St. Maarten and love to work with my hands as a hobby. I work with wood mainly because easy to obtain and work with building things to help me. I have recently finished my small work space and would like to venture in other craft. As I mentioned using CNC to route wood laser engrave plastic and the like. I do not have the financial means to buy expensive equipment because on an island everything have to be imported. With this in mind and strictly for learning and hobby I would like to build a small machine. I have visited this site often to learn about this craft and must say I have been educated by all the posts. One factor that prevented me from building a machine is the costs of the components such as rails etc, but I have noticed that prices for these items have dropped and prove to be be better alternatives to what was available years ago. Therefore I feel now is the time. I have access tools such as a drill press, table saw, engineers squares, calipers and a few other tools.
I know that there are a lot of cheap Chinese designed machines, but I am firm believer that creating something is the best teacher. Some of the designs on this site are well though out and inspiring.
I need help in working out the basic dimensions for a machine that can route a 400 x 300 work area.Fixed gantry. To cut plastic, mount a laser engraver, or machine aluminum. I also noticed designs with welded tubing, how is compensation for made warping that comes from heating metal? How do you get accuracy for from such a machine? I ask this because tubing is readily available but if I have to machine a welded item to make accurate it can be expensive on this island.
From the posts I understand ball screws, rails, but would really appreciate your kind assistance in helping me realize my dream.


Regards;

Larry Alexander

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Originally Posted by Symbot3

Good Afternoon all;

My name is Larry Alexander and for years I have been interested in CNC. I live on the island of St. Maarten and love to work with my hands as a hobby. I work with wood mainly because easy to obtain and work with building things to help me. I have recently finished my small work space and would like to venture in other craft. As I mentioned using CNC to route wood laser engrave plastic and the like. I do not have the financial means to buy expensive equipment because on an island everything have to be imported. With this in mind and strictly for learning and hobby I would like to build a small machine. I have visited this site often to learn about this craft and must say I have been educated by all the posts. One factor that prevented me from building a machine is the costs of the components such as rails etc, but I have noticed that prices for these items have dropped and prove to be be better alternatives to what was available years ago. Therefore I feel now is the time. I have access tools such as a drill press, table saw, engineers squares, calipers and a few other tools.
I know that there are a lot of cheap Chinese designed machines, but I am firm believer that creating something is the best teacher. Some of the designs on this site are well though out and inspiring.
I need help in working out the basic dimensions for a machine that can route a 400 x 300 work area.Fixed gantry. To cut plastic, mount a laser engraver, or machine aluminum. I also noticed designs with welded tubing, how is compensation for made warping that comes from heating metal? How do you get accuracy for from such a machine? I ask this because tubing is readily available but if I have to machine a welded item to make accurate it can be expensive on this island.
From the posts I understand ball screws, rails, but would really appreciate your kind assistance in helping me realize my dream.


Regards;

Larry Alexander

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Welcome to the forum

For 400x300 cutting area you would need an extra 200 mm or so on each axis for a moving gantry router, so about 600x500. For a moving table you would need more space to allow the table to move to each extent. So assuming 400 is across the gantry and 300 is the moving direction then footprint would be ~600 x 600. Of course this is a guide so start by drawing the full sweep of the table, add the fixed gantry legs on each side and the Y axis which moves across the gantry and you will start to see what you really need based on fitting all the bearings etc in and spacing them out to give enough support and allow it to be assembled in terms of bolt access. Do you have a CAD package to use ?
Also at 400x300 I’d probably go for moving gantry to keep it a bit more compact but either would work.

A welded steel frame is fine if you are careful with the weld sequencing, but I would expect it to need some form of levelling still. You can shim the rails level if you have a good straight edge and engineers level, or you could try epoxy levelling to create a flat surface. However having built a few machines and tried different methods I would get them machined flat but sounds like that might not be an option for you.

Welcome for the forum. St. Maarten?, let's look on the map....

...right... if you cover flights, accomodation and bar bills I think we should be able to get a design team to come out to help for a couple of weeks? I'll bring the paper and pens. Just let us know when's good for you...

I do recognise your desire to build to learn, a good thing in my book...

You start by describing what could be a rather conventional and simple build with cutting plastics and laser engraving, then you throw machining aluminium into the equation as well. Up until you added aluminium I'd have suggested investigating whether a laser cutter/engraver would be more appropriate - that's obviously your call to investigate; shipping must be a major contribution to the purchase cost so if may be cheaper to buy a complete machine that organise shipping for individual components.

Is your cutting area for aluminium similar to that for wood/plastic? Are you sure that you're looking at a single-machine solution?

Look at some of the build logs - if you've not already done so - there's been some superb examples of builds with hand tools. Create an entry in the build-log area and start posting your sketches for a design - you'll soon attract comment and criticism :) - all constructive, of course. You're better placed than most to plan before you buy here.

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Originally Posted by Doddy

Welcome for the forum. St. Maarten?, let's look on the map....

...right... if you cover flights, accomodation and bar bills I think we should be able to get a design team to come out to help for a couple of weeks? I'll bring the paper and pens. Just let us know when's good for you...

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I'm not going all that way for a couple of weeks. If he covers flights, accommodation, and bar bills for 3 Months, I'll take him a finished machine in my suitcase..:encouragement:

Maybe take a leisurely trip over there when the Star Flyer returns for its winter season

Seriously symbot3 Welcome
You have come to the right place . Helpful and knowledgeable people on here so I am sure you get the help you need .
It is a steep learning curve and each step forward prompts another question(or two)

I have been in the process now for a few months in a serious way so I still have a long climb , but this is the place for info.