[Zygoat]

pretty sweet. i want that.

[InventIt]

Just a little update. Have not done any work to the cnc machine, but I have been using it.

Nothing real exciting... My boss needed these covers for a machine at work, so I volunteered to make 'em.

Made out of 1/4" Macrolon (polycarbonate). Very simple, just a flat top with a left and right side panel. Sides are joined with a bevel and glued. I am using a 3/16" carbide router single flute and a 1/2" Dia x 45* Vee bit for the beveled edges. Both at 6000 rpm, 60 ipm.

Made a vacuum jig out of MDF and plywood to hold the plastic blanks for machining. I had to add the clamps to the small pieces because they are too small in surface area to hold during a cut. The vac pump is a Becker vane style and produces about 27" hg. This was my first time using a vac jig for work-holding, works really well and I will definitely be using this method again

[ame=http://www.youtube.com/watch?v=Pe76JvTDuMQ]Machining Covers pt1 - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=ZeqDr2KV4zY]Machining Covers pt2 - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=F00ltFkDdz4]Machining Covers pt3 - YouTube[/ame]

[judleroy]

When I have made similar parts in polycarbonate acrylic etc... I take a slightly different approach. Instead of cutting 3 pieces and gluing them together I will score them and then heat the scored area and bend to 90. The score should be half way through the material with a 45 deg v cutter. In a 1/4 inch thick piece the score would be 1/8 inch deep and 1/4 inch wide. This leaves a lot more strength to the part. Also for a side note with polycarbonate up to 1/4 inch thick (can do thicker but not recommended without heating) you can skip gluing altogether by using a metal break.(not the flimsy breaks for vinyl siding). Just mark the Id and clamp in break then bend to desired angle. This will give the strongest part possible.
Judleroy

[InventIt]

When I have made similar parts in polycarbonate acrylic etc... I take a slightly different approach. Instead of cutting 3 pieces and gluing them together I will score them and then heat the scored area and bend to 90. The score should be half way through the material with a 45 deg v cutter. In a 1/4 inch thick piece the score would be 1/8 inch deep and 1/4 inch wide. This leaves a lot more strength to the part. Also for a side note with polycarbonate up to 1/4 inch thick (can do thicker but not recommended without heating) you can skip gluing altogether by using a metal break.(not the flimsy breaks for vinyl siding). Just mark the Id and clamp in break then bend to desired angle. This will give the strongest part possible.
Judleroy

Thanks for the pointers. I'll have to try those methods. But I can't do it on this project though, I am limited to building the cover the same as what is aready on the machine. Our machines have 10 of these covers and I have to make the new cover match the old cover.

[CROSSHATCH]

An awesome build. I want to read through everything.

Finishing up my last year as an MET. I need to start designing a machine like this for the future, this is a great machine.

Build be me for my shop? Not as complex...but gawd that tapping head was sweet!


Excellent job.

-Jason

[CROSSHATCH]

Any updates? If you don't mind me asking, how much did the frame cost for them to machine/weld etc. I'm thinking about building a similar machine.

[toranacar]

Good questio
Just wondering would large I beams be a way to go when building something like this? I beam frame, gantry etc

[InventIt]

Any updates? If you don't mind me asking, how much did the frame cost for them to machine/weld etc. I'm thinking about building a similar machine.

Machine work was about $2000

No updates. Just been using it.

Been a little too cold here to work on it but I did buy a few extra sets of bearing blocks. I plan on adding a third bearing block to the Y axis to get more rigidity. May also change out the acme screws for zero back lash ball screws. Also want to shorten the Z axis to 12" of travel (about 10" less height)

[InventIt]

Good questio
Just wondering would large I beams be a way to go when building something like this? I beam frame, gantry etc

I believe I-beam would be more flexible. Box cannot twist like open I-beam can. If I did it all over I would spend the extra $$ and made the base heavier. Machine want's to jump all over the place when the motors are tuned for hi performance.

Of course it all depends on what you want to cut and how high a MRR (material removal rate) you expect.

[toranacar]

Very good point, box beams with half inch walls? 10inch X 5inch?

I believe I-beam would be more flexible. Box cannot twist like open I-beam can. If I did it all over I would spend the extra $$ and made the base heavier. Machine want's to jump all over the place when the motors are tuned for hi performance.

Of course it all depends on what you want to cut and how high a MRR (material removal rate) you expect.

[CROSSHATCH]

2k is a great price! Now i'm excited!

[InventIt]

The warm weather we have had lately motivated me to work on the Y axis improvement I have been planning. This was a simple mod in an effort to help improve on rigidity. I had previously bought extra bearing runner blocks for the Rexroth 25 rails on the y axis. I am increasing the mount from 10" in length to 15" and adding one more runner block for a total of three runner blocks. I will do this to both sides of the gantry. This should improve rigidity of the gantry.

First pic shows the original 2 block mount
2nd pic the gantry is lifted slightly and the mount removed
3rd pic was drilling the 9/16 holes on the Bridgeport where the gantry bolts to the mount
4th & 5th is a pic of the new longer mount with the 3 bearing blocks installed

Next mod will be to shorten the z axis travel by about 10". I find the weight of the z axis sticking out so far (and cantilevered) from the gantry seems to be a problem when changing direction in the y axis. I haven't decided if I want to modify the existing z axis or make a new one and save the old one for another project.

[InventIt]

2k is a great price! Now i'm excited!

Yeh, I guess I got a good deal on the machine work. I went back 6 months later to have the same shop machine the z axis plates (3 steel plates, 1"x8"wide and 12-28" long, surfaced with a few holes drilled and tapped, fairly simple) and he wanted $2500 !!!

That's how I ended up with a series II Bridgeport in the shop

[CROSSHATCH]

I'm looking to have a shop do some work for me. Mainly a frame with some minor machining/lapping/tapping ydadada

You built your table right? That's my problem...the shop would need to do it.