Diary of a FoamCutter building a jgro router table

[mcyr]

Hi Mark,

Funny you should point those articles by Phil Pearson in RCSD out. I read though them this weekend between reads on building a cnc router. I'm so excited I ordered my bearings last night and will start my router build sometime this weekend. Thanks for the link.

Dave, sorry...not trying to steal your thread...back into lurking (and construction for me!!!).

Do have a question about what software you are planning on using though...what are your CAD and CAM program plans?

Mike

[Glidergider]

Markg:
Explain further how the encore wing is made? I'm not getting it from the article. Maybe its just reading it on line. I understand the first side of wing surface is cut in the missionary position. I'm mean, nothing fancy, it just lays there flat. But once that surface is cut, a female form is used to hold the flipped wing? So a separate negative surface must be cut too? And, its the negative surface that has the vacuum holes right?
Dave

[mcyr]

Dave,

That's exactly right. Phil mentions in this article that the female foam "holder" has a special arrangement of holes for vacuum to handle the thin material left at the trailing edge. Evidently the cutting bit creates a "thermal" and tends to lift it. Really innovative stuff Phil has done on the Encore and has shared with us.

Ordered my steppers and drivers from HobbyCNC tonight. Guess I'm in for the long haul now.

Mike

[MARKG]

Hi Dave,

I think the female form for routing the flipside of the wingcore is part of the "800 hours" of development mentioned in the articles that went into the setup that allows Phil Pearson the crank out Encores reliably and repeatably.

It's certainly a level of precision we can all aspire to.

Back to my router project too...

Mark

[Glidergider]

Mcyr,
congrats on your purchase of the hobbycnc system. Its a good product. I've got to decide if I want to solder up the boards myself, or just buy a complete system.
Dave

[Glidergider]

Up to now, I've been building my JGRO with just the pdf drawings. Now I have a question about the dowels. On the plans, I see several holes at .250 inches and a cross-hairs (CG symbol). I'm assuming these symbols are for the dowels.

Can someone confirm?

Next question: If these holes are for the dowels, what is the strategy for drilling? Drill these holes after assembling?

Thanks,
Dave

[HayTay]

Up to now, I've been building my JGRO with just the pdf drawings. Now I have a question about the dowels. On the plans, I see several holes at .250 inches and a cross-hairs (CG symbol). I'm assuming these symbols are for the dowels.

Can someone confirm?

Next question: If these holes are for the dowels, what is the strategy for drilling? Drill these holes after assembling?

Thanks,
Dave

Yes these 'extra' holes are for dowel pins. I drilled mine before assembling the Gantry and everything fit together nicely except as noted previously. I don't see where drilling the alignment pin holes after assembly would make much of a difference.

I wound up using 1/4 x 1 1/2" steel dowel pins from McMaster-Carr - Part No. 98381A546 - $10.73 US for a box of 50.

[Glidergider]

Hi HeyTay,
Thanks for the insights.

I've been on company travel for 2 weeks. So glad to be home with the saw dust. I didn't waste any time getting back into the swing of cutting wood. Next I need to buy a 1 inch dia. hole saw. I was surprised how the 1.5" hole saw would gum up during the cutting.

Here's a picture of my progress. Its a pile of cut wood, but it tells a story of my progress. I'm not the best craftsman, but in the end, this thing is going to cut wood for me.

Whats the favorite software? Mach3, TurboCNC? Is there a poll out there somewhere in the past? I noticed Mach3 is on sale for $159 right now.
Dave

[tajord]

Mach 3 is the way the go, did you download the demo, if not try it and run the roadrunner simulation, kinda cool to watch, and it'll get you familiar with the software too.

[HayTay]

Next I need to buy a 1 inch dia. hole saw. I was surprised how the 1.5" hole saw would gum up during the cutting.

Try a 1.5" Forstner bit instead. I had the same problem with the hole saws. Other people seemed to have better success with the Forstner (type) bits. Just a suggestion.

As to software, Mach3 and VCarvePro 3.1 seem to be the way to go. Both are relatively inexpensive but packed with more than enough features to "get the job done".

[Glidergider]

I did download the Mach3 demo. I even uploaded some of my dxf files used with the foamcutting machine. They loaded easily and looked like they would cut without incident.

In Mach3, is there a tool that easily offsets the router path half the diameter of the cutting bit?

Also, I took a good look at vcarve family of software. There are three products. Does the VcarvePro (the most expensive) do the functions of all three software packages?

I'm not sure of the difference between vcut and vcarvePro. Any ideas on the differences?

[edo]

I'm using Mach3 with great results and it'll do tool offsets, but I wouldn't say it's easy. It took me a lot of 'air' cutting to figure these out.

You have to manually edit the G Code by inserting a G41 (Radius Offset Left) or G42 (Offset Right) command followed by the tool radius or tool number. You can store your tool sizes in a table in Mach3 and reference them by number. The offset left or right is dependent on whether you're cutting inside or outside the vector as well as the direction of the toolpath (CW or CCW). You also have to set up for the offset by using the G41/G42 command prior to moving to where you're going to start cutting to give the machine the time to move into the offset. And something I still haven't figured out, when using the offset to cut arcs (G02/G03) the machine sometimes gets goofy and just goes off cutting circles.

Whenever I use offsets, I always run the program with the power off to my controller just to watch the cutting path in Mach3.

[Glidergider]

Edo,
Very interesting info. I wouldn't call it easy either. A puzzle for people who like puzzles.

Here is my progress for tonight. I had a discarded nylon cutting board laying around and I've been eyeing it closely. Wondering if the thinner section would work for the adjustment blocks. So on the small blocks I decided to try it. I'm very pleased. I have one more to make.

Heres a picture.
Dave

[HayTay]

I had a discarded nylon cutting board laying around and I've been eyeing it closely. Wondering if the thinner section would work for the adjustment blocks. So on the small blocks I decided to try it. I'm very pleased.

Dave,

With the thinner material, will there be enough clearance/room to (easily) turn the adjustment bolts when the adjustment blocks are attached to the machine?

I just wanted to drop you a note so you could make sure before you got too carried away.

G'night for now,

[Tony Mac]

Hello Dave,

The 3 Vectric products offer different functionality.

VCarve Pro - General 2D machining with automatic cutter radius compensation for Profile and Pocket machining. Decorative 3D V Carving and precision engraving, Drilling and 3D Texturing.

VCPro imports most 2D vector based file formats - DXF, EPS, AI - with design editing tools for sizing, positioning, node editing-fixing etc. very good 3D toolpah preview, estimates the machining times and includes postprocessors for most CNC controllers.

Cut3D - Is a 3D machining package for cutting 3D models that have been designed using CAD / Design software such as Rhino3D, Silo, AutoCAD or designs available off the Internet.

Very straightforward to use with options to machine a single face of a model, 2 sides Top and Bottom or 4 sides top, bottom, front and back.

PhotoVCarve - Is for engraving / carving decorative pictures and lithophanes (3D back-lit photographs).

The files from PhotoVCarve can be imported into VCarve Pro and positioned relative to other design elements such as a decorative border and text. So for example a complete picture frame can be designed and machined.

I hope this above helps and let me know if you have any questions.

Tony

[Glidergider]

Tony Mac,
Thanks for the info. That is some pretty good looking software, but together the price!!!! Some of the stuff it can do looks amazing.

HeyTay,
Good point about it being to thin to make adjustments. I'll see if I can make it work, but yes the bolt heads will scrub the MDF base. I might try shimming, and if all else fails, I'll rebuild them with 3/4 inch. If it wasn't for the adjustments, I believe the strength is there.

I do have another question about the Z axis. With the gas pipes vertically suspended, what mechanical structure supports the gas pipes and resists the pipes from pursuing their ultimate goal of reaching the center of the earth?

Thanks for the comments. Building is fun!
Dave

[Jtheletter]

Hey Glidergider, I've been following this thread with much interest since it looks like you and I are getting JGROs built almost in parallel. For the alignment blocks and antibacklash assemblies I used HDPE which is just a high-density version of most cutting board materials. It's fantastic stuff to work with and I found it was well within my budget to order from McMaster Carr. Check out my thread on HDPE blocks here to see all the details including links to McMaster and prices.

I'm approaching finally assembly myself this weekend, would have been done a lot sooner if my car didn't keep falling apart and eating all my spare time. Anyway, I'll probably have some photos to add to this thread come Monday if you all don't mind me jumping into the fray.

As for the z-axis rods I found that they are very securely held in place with the HDPE alignment block screws, and since there's not going to be any downward pressure from the rail slides (they will put pressure perpendicular to gravity) I don't expect much downward slipping. If it does turn out to be a problem, drilling a couple indents for the alignment block screws to sit in will probably correct any problems.

Keep up the good work!

[Glidergider]

Hi Jtheletter
Thanks for the notes. Go ahead and add some pictures. I cut the antibacklash nuts last night, and I'll post pics tonight.
Dave

[Glidergider]

OK, I'm about to start assembling the Gantry. (cnc_assy07). On detail 16 and 17 (the sides), I think there is missing some callouts for tapped holes in the bottom edge.

I'm also wondering if there are written instructions for the Gantry assembly. I don't want to put it together crooked. If you know of some instructions, help me find them please.
Dave

[Glidergider]

Here's a picture of the Anti-backlash nuts. I'm happy with them. Made from my wifes discarded cutting board. I also mounted the small adjustment blocks.

Tonight I hope to get the major parts of the gantry assembled. Any advice on what to connect to what first would be appreciated.