[rjfurness@bigpo]

Hello All,
I will be posting a build thread for a CNC Foam Cutter made from the plans available from

http://www.drayconstruction.com/foamstuffs/

I have ordered a HobbyCNC kit with driver board and steppers. My experience with these for my first router project was that the kit was great and easy to build.

I have the drawers slides from old prototype products from work, I think I have enough MDF in the garage. I need to buy and extra length of threaded rod. I will be using the rod from my first router for most of my needs.

I will begin to post pictures tomorrow.

Jason Furness

www.cashfocusedcoaching.com

[rjfurness@bigpo]

Been to Bunnings to get a few bits and pieces for the build. I will be replacing the triangular gusset pieces with metal right angle brackets. It just saves me cutting things up and trying to get them square.

I am priming up the MDF before cutting it all up.

Dave Rigotti from HobbyCNC has emailed me to say they will despatch my driver boards and steppers on the 29th. I should have the framework all made up and ready to attache the motors to by the time they arrive.

As the steppers are NEMA23 mounts I can use my 300oz motors from my router to get the attachment points right and to test run the axes.

I will post some photos later today.

My goal with this machine is to cut wing and fuselage compnents for my radio control planes. I have a plan for a twin engine OV10 Mohawk by Vance Mosher that I would like to cut on the machine.

Jason

[rjfurness@bigpo]

Hello All,
below is a close up of the threaded rod and drive nut I will be using. Pretty basic, but it worked well for my prototype router. You can see where the end has been turned down to be the same diameter as the stepper motor shaft.


The next shot is just the primed MDF board and bits and pieces. I will be using some steel right angle brackets instead of the wooden triangular gussets for the X-Axis. Mainly because I could not be bothered cutting them out of the large MDF sheet and ensuring the angles are accurate.



I will collect the drawer glides today as well as the extra threaded rod I need.

Jason

[rjfurness@bigpo]

[IMG][/IMG]

[IMG]

Not sure why they didn't post but here they are.

[rjfurness@bigpo]

Here are the slides for use. The larger ones are for the X-Axis and I think are designed to support 50kg+ each. I will pick them up from work once I get the paperwork sorted out. They are surplus from some prototyping work.

[IMG]

Jason

[rjfurness@bigpo]

Just got an email saying my controller board and steppers have been shipped from HobbyCNC. I have all the bits to get started on Sunday assembling the Axes.

Jason

[miljnor]

I think im going to do a little one like this. good luck and it should be fun!

[jhelmstetter]

Right angle brackets will definitely save you some cutting but make sure that the brackets are truly 90 degrees. I have seen some that are bent a little less than 90.

I have built the Dray's and it is a simple and efficient build. The only thing I didn't care for, and it could be my own fault, was the way the lead nuts attach to the axes. You'll probably never have an issue if you don't hit the physical travel limits but the epoxy broke loose easily when I did.

I also found that if your lead screws are not perfectly straight you will get the wobble that will transfer into your cuts. I am in the process of creating a lead nut attachment that will basically allow the screw to wobble some and not effect the cut. This method could induce a small amount of backlash but that will all be in the testing.

I'll keep the forum advised of my progress.

Joe

[rjfurness@bigpo]

Thanks for the comments.

I do agree the epoxy only fixing of the leadscrews is vulnerable to breaking. I will be using some form of a stop to assist. I might use some washers screwed into the MDF and overlapping the lead nut to have the force transferred through the washer rather than the epoxy joint. I will make it up as I go along.

Jason

[rjfurness@bigpo]

Progress for the day!

Here is the Y-Axis Asssembly.
[IMG][/IMG]

It is all screwed together, no glue or nails.

Here it is mounted on two drawer slides,ready to be screwed to the X-Axis base.
[IMG]

One of the X-Axis slides is different than the others so I will replace that tomorrow just in case there is a difference in the travel.

This is really a very simple machine.

Jason

[rjfurness@bigpo]

HI All,

[rjfurness@bigpo]

Hi All,
I am looking at using the Profili software to drive my foam cutter. It looks to do exactly what I want for RC wing cutting. Has anyone got experience with this software?

Thanks

Jason

[billscottuk]

Hi All,
I am looking at using the Profili software to drive my foam cutter. It looks to do exactly what I want for RC wing cutting. Has anyone got experience with this software?

Thanks

Jason

Profili is airffoil ploting software, not sure it will do what you want. Most foamcutters use GMFC, fcut or jedicut

[jhelmstetter]

Yep Profili will provide you with a whole ton of wing profiles and give you a lot of information that would probably make sense if you are an aeronautical engineer. It will also let you create your own NACA wing profiles and if registered, you can even export them to DXF format.

Okay, so here's my idea for the "floating" lead nut. If you take a piece of HDPE (high density polyethylene) and cut it square. Then tap the center of the square with the 1/4" tap or whatever lead screw you are using. Here's the trick, drill 4 oversized mounting holes. When you attach the lead nut to the axis, tighten the mounting screws to the point where the lead nut gets snug and then back off the screw a little to allow the lead nut to move slightly without pulling away from the axis. This should compensate for any wobble that is induced from the lead screw and at the same time limit the amount of backlash from the loose mount. I will try it out on my Dray's and let you all know how it works out.

Joe

[Crash-Man]

Jason, I'm watching your build closely as I purchased the same set of plans today.

BTW, how long did it take them to email you the PDF e-book plans? I ordered about 13 hours ago and still haven't received the email from them (they say the you will get the file immediately).

Keep up the good work!

[rjfurness@bigpo]

Hi Crashman,
I got the plans within a few seconds. The plans arrived via an automatic email so I suspect a problem with the address or server.

Jason

[Crash-Man]

Must have been something wrong with their server or my email. However, I called them up at the number provided on my PayPal detail, and they took care of me. Now I'm off to the hardware store to get some MDF. Fortunately, I have an overhead gantry CNC machine to cut out my parts. I seldom cut anything on the table saw anymore!

[miljnor]

I know what you mean...i have a table saw that just sits and collects normal dust not the good wood-chip variety!

[rjfurness@bigpo]

Hello All,
here is a picture of an almost completed side of the machine.
[IMG]

I expect to get my steppers and driver board this week. I am also getting the ends of my lead screw rod turned down to match the stepper diameter. I am waiting to get all of these parts together before I start to add the mounting plates for the motors and the plates to attach the lead nuts to the axes.

Jason

[rjfurness@bigpo]

Hi All,