Question on Table Offset
 

Hello everyone, I am now making good process. I have three different projects going on all at the same time.

1. Steel Construction:
a. Material cut for final assembly.
b. Welder Purchased (waited for sale)
Cost $450.00 Lincoln 175HP - This purchase was driven by other needs.
1. Continuous voltage control
2. Wide current range (25-175A) handles 24ga up to 5/16"
3. Comes with a gas regulator suitable for Argon/CO2
4. Available stainless/aluminum kit

2. Kitchen Project:
a. Shop for parts via Internet and local looking for quality with price in mind.


3. Cheap Chinese Spindle:
a. I eventual wanted a spindle and could NOT past up the opportunity to purchase it at a reasonable price.
b. I know this is going to delay my completion by weeks.

I have several questions in all areas and will asked them in separate replies.

Gerald.

Table Question:

Is there any harm in aligning the 6 middle cross bearing beams and the table legs around the centerline of the table frame? The outside cross bearing will still reflect the table surface offset of 3.9. I am about to weld the legs onto the main beam and realized that I drill the cross bearings holes on the frame centerline instead of the table center.:mad:

Here is a picture of my table progress.

Donna, from a strength/stiffness viewpoint, it is only the distance between the cross beams that matters, and not how evenly they are spaced. We are trying to keep the maximum space at under 16" [400mm]. You are going to have one wide space, 5 standard spaces and then one narrow space. The wide space is at the end that is going to see the most work, is it possible to lay an extra beam in that space? If your wood table surface is fairly thick, you could perhaps go wider on the beam spacings, but the wood wears away with time.

What size (and thickness) is that angle material that you have for the cross beams? It may be more more flexible than the channels on the drawing, in which case it will not be good to go wide on that one space.

The legs can go nearly anywhere.

Thanks Gerald for your quick response. As talked about in one of my earlier posting, I cut my cross bearings from C8x11.5. I attached a closeup picture. The side bolted to the main beam is 3" and standard side is 2". These cross bearings are heavy than what is in the drawing. They are also bolt with 1/2 recycled bolts. I don't think the table surface will experience any extra load, but you are the professional. What do you think?

Donna, you are going to be surprised at the strength comparison . . .

From http://www.engineersedge.com/standar...properties.htm:

For the C8x11.5:
I_xx = 32.6 in⁴
I_yy = 1.32 in⁴

For the C3x5:
I_xx = 1.85 in⁴
I_yy = 0.247 in⁴

These are the (stiffness) numbers which are proportional to the resistance to flex in the beams for a given load condition. It can be seen that when the channels stand up straight, they are much stiffer than lying down flat.

The 3" channel standing up straight is stiffer than a 8" channel lying flat (1.85 versus 1.32). But you cut the 8" channel in half, so it's number becomes 0.5x1.32 = 0.66.

Even though your half 8" channels are heavier than the 3" channel. their shape only gives them 0.66/1.85 = 36% of the stiffness. Sorry that I only calculated this out for you now.

Gerald, this is not a problem. If the table appears to be unstable, I will replace them with more recycled channels. I have the resources. Currently the spacing is 13.75".

What about my question of the offset?

Okay Gerald, after reading my question and your reply, it appears that you think I only 6 cross beams. I have 8 cross beams with a spacing less than 16". The two beams on each end will be adjusted to miss the legs.

To give it more strength, I will add 4 umbilical plate to help tie them all together. Placing them symmetrically around the centerline of the table frame.

As stated before, if this appears to be unstable, I will replace them with recycled C3x7.

I meant that the following addressed the offset issue:

From "You are going to have one wide space, 5 standard spaces and then one narrow space" it can be seen that I realised you would have 7 spaces which means 8 beams. Knowing now that your spacing is 13.75", and with the offset of 3.9", it follows that your 7 spaces will be:
17.65"
13.75"
13.75"
13.75"
13.75"
13.75"
9.85"
(PS - this gives a total table top length of 98.6". Is that what you want? See 10 10 123 D)

and thus: "The wide space is at the end that is going to see the most work, is it possible to lay an extra beam in that space?" meaning that you could divide the 17.65" with a 9th beam.

But then I saw in the photo that you were using relatively light angle and not channel. (I must admit that I don't read everyone's posts in detail to analyse deviations from the plans).

The ShopBotters were working with angle iron beams before and their early tables were just not stiff/stable enough for many applications requiring precise z-depth control. If you are going to be boatbuilding and cutting out plywood sheets, your table as it is now will be fine. The signmakers who tried cutting a flat background between raised letters suffered with the flexible tables - they had ridges that needed sanding between the letters.

Adding umbilical plates will do nothing for table stiffness.

I added the following note in post #2 of 1010302S Cross Support Beams under table top :

Here are the minimum L-sections that will be about as stiff as the C-section in the drawings:
80x10 [ L3x3x3/8 ]
90x6 [ L3.5x3.5x1/4 ]

Hello guys,

I know it has been sometime since my last posting but I am still here. Work and family has distracted my physical work but not my research on building MM. Soon I will post my water cooling system for the 2.2kw Chinese spindle. I'm still waiting on parts and plan to build my own controller.

I wish everyone on this site a merry Christmas and a happy new year.

Merry Christmas Donna! Good to see you are still around. You are still in the running for first female to build a MM! :)

Motors Turning
 

Hey everyone, Gary got our motors turning. He will post pictures today.

Well done Gary!!

I must admit that I was worried when he battled with the contactor :o. But I love it when folk prove me wrong! :D

Alive and well in Suwanee GA
 

We have made some progress just sending pictures to document the build.
Will send more in the near future. The Kitchen project went well and we have finished all the welding and most of the painting we are currently wiring the machine to the control box.


Attachment 12302

Attachment 12303

Attachment 12304

Attachment 12305

Attachment 12306

Some more Pictures
 

Painting went well and we have started and finished the rails.

Some more pics
 

Here are some more pictures of the rails. The rails went pretty good but i did have to buy an extra 10 foot section because i had problems lining up the skate.
Not our finest moment but we did okay. Once we figured out that we needed to cut the rails then placing them back to back we then grinded them level.
The last pic was the making of the stops

Additional Progress
 

Here are some pics of the Z slides and spider assembly.

Lookin good !!!

Still making progress
 

Still making progress here is a picture of the water cooler, 12v pump and enclosure with glass reservoir pump is very quiet.

lots of progress
 

Here are some pics of our progress will try to post some pics later
the motor connectors with 3 black wires and one yellow were really fun. keeping up with your pin-outs and troubleshooting a bad connection can be pretty time consuming. It is still good to be finally connecting the machine to the control box.

Some more wiring pictures that first gantry 3 button box get full quickly a oversize 3 button box is a must.

Some more wiring Pic
 

Had to change that small 3 button box keep those labels coming.
What a relief to finish the wiring everything seems to be working fine.
The VFD is connected and working time to start cutting.
Spindle temperature 115 degree f after running for three hours still need to address that issue.
setting-up and configuring mach3 will take some time, back to the drawing board lots of reading still to do.

Donna;

Very Nice!... I am trying to catch up with you :).. Hopefully this weekend I will get closer.

Miguel

Cutting in Suwanee
 

Hi: Miguel hope you had plenty of success this last weekend.
I must tell you that once you get the machine to work the real problem is getting the machine to follow instruction with g-code we had problems generating g-code because we thought generating g-code would be easy. Donna is very good in Autocad and we just assumed generating g-code would be easy. Finding the right application to generate g-code is not hard there were plenty of free application that generated g-code but you must still do your research on how to use each application for your needs. We ended up using g-simple to generate g-code just to get us cutting we may have to use something else for production. I will give some screen shots on how to use g-simple found at g-siimple.com. Today the pictures will show the results of the our machine cutting we still have issues when we hit the ref all button our Z hits the stops and we don't know how to stop it from doing that. But we can get the machine to cut words hopefully this is enough to get a serial number. Here is the link
http://www.youtube.com/watch?v=EZSyNHxgufs

Hey, it is cutting - well done Donna & Gary!

Yeah, it is bit of a surprise when the machine starts cutting lines in the same sequence that you drew them in AutoCad. SheetCAM was a great little program a few years back, maybe still today.

Congratulations Donna & Gary - well done. Now the fun will start :)

Congratulations - your cutting.
Now the real fun begins...what do with that great "tool" in front of you? :)

Best to you both!

Well done and enjoy the addiction

Congratulations! :)

Lookin great !!! All we need now are some logos !!

Logo
 

Thanks everybody
I had so much trouble getting the camera to load video i forgot to show the logo's
Here they go let me know if i need to submit another video.

Gary

Dust, logo, I think a serial number is due ;)

Awesome job! Welcome to the biggest addiction of your life :)
If I can help in any way please let me know

Cheers
Tim

To much dust
 

Any suggestion on how to make a dusk shoe?
I have dust everywhere and it is getting hard to clean-up. I have vacuum equipment but no idea how to create an dust shoe been reading all day and still drawing a blank. Appreciate any help.

Thanks
Gary

You can use faster spin up time for the spindle, I got mine set up at 100hz/sec and its just right for automatic start up on program start.
If you got the RS485 on the Huanyang VFD its easy to set it up to start automaticaly and set speed from gcode.

Look here for dust shoe
http://www.mechmate.com/forums/showt...&postcount=290
http://www.mechmate.com/forums/showt...&postcount=427
maybe it will get you some ideas

This machine has been an addiction of mine for years before I started this project. I like to thank Gerald, everyone on this forum and my husband who continued to work hard to complete our dream:)

I was looking forward to making dust, but this is way too much. Dust shoe is on the list.

#87 it is !! Congrats on your build !!! Enjoy the dust !!!

Builder's Log Update
 

Donna,

Congratulations on a great looking MechMate and earning Serial #87. Nice job!

Here is the Updated Builder's Log.

Please review your entry and let me know any changes you want to make.

Another dust shoe suggestion: http://www.kentcnc.net/nc/

Congrats!