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3-axis CNC Machine Kit - Model 1100X
I just got into the CNC world less than 2 month by buying my first Sherline CNC mill 2000. Sherline is really a great machine. However, it has it own limitation, from size to
spindle power. This made me think about building my own with a comfortable dimensions for my applications. However, the idea grew greater to make a CNC Machine kit that easily assembled for anyone who needs it and don't want to go through the hassle of design. I saw a lot of home made machines in this forum, but the one that got my attention is RicknBeachcrest 's thread :wave:. I based my Model 1100X on his design with some tweaks that make it easily assembled and disassembled to be introduced as a kit. One of the major differences that I am using metric extrusions
instead of fractional. Also, I tried to make each axis by its own as a unit.
Currently I am in the design phase. I attached the 3 axis design concepts in 3D. More detailed photos will come.
Attachment 232436Attachment 232438Attachment 232440
Re: 3-axis CNC Machine Kit - Model 1100X
I'll be very interested to follow your build. Have you looked at Senna's build?
http://www.cnczone.com/forums/diy-cn...et-router.html
I based my build upon his.
Good luck.
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The Model 1100X design is finally finished
I finally finished the design for the Model 1100X. Time to shop for some extrusions (nuts)
Here are some photos of the different views for the build. Feedback guys
Attachment 232730Attachment 232732Attachment 232734Attachment 232736Attachment 232738
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Quote:
Originally Posted by
RicknBeachcrest
Yes I saw it. It is very nice too. I uploaded more photos check them out.
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Re: 3-axis CNC Machine Kit - Model 1100X
I had a couple of thoughts ref. extrusions. Keep in mind that extrusions are not all the same, for a given dimension. Take a look at the specs., specifically the Moment of Inertia. I've attached a pdf from the automation4less website that gives the tech data for their extrusions. Automation4Less is a great place to deal with. Misumi is another good supplier of extrusions (and other motion control parts). And of course there is 8020 garage sale on ebay. Also extrusions are heavy and will not be cheap to ship, be prepared for this cost. Speaking of cost, the brackets and nuts & bolts will add up quickly. Go over the amount you need and then double and triple check your numbers.
I would recommend using gussets, as opposed to angle connectors whenever possible. I would use gussets (at a bare minimum) for your connection of the gantry to the bearings. In fact, I would move the gantry to the bearing that is on the opposite side of the spindle. I know it's here because you are spanning both bearings with that angle bracket. I think you may need to re-think this connection.
These are just my opinions as I am definitely not an engineer. But I have been reading these forums for a couple of years.
Good luck
Re: 3-axis CNC Machine Kit - Model 1100X
A single middle screw on a moving gantry machine is just not adequate in my opinion. Far too many problems.
Re: 3-axis CNC Machine Kit - Model 1100X
This is looking good.
I did build my first router with a center screw, but you have to build in adjustments to put pressure on the X bearings in order to eliminate racking. That and spreading the bearings as far apart as possible with help.
That said, I would not do a central screw design again. Putting a screw on each side of this design will considerably reduce gantry weight and double the strength to move the gantry. It does add cost, but I think the benefit is there to make that worthwhile.
Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
RicknBeachcrest
I had a couple of thoughts ref. extrusions. Keep in mind that extrusions are not all the same, for a given dimension. Take a look at the specs., specifically the Moment of Inertia. I've attached a pdf from the automation4less website that gives the tech data for their extrusions. Automation4Less is a great place to deal with. Misumi is another good supplier of extrusions (and other motion control parts). And of course there is 8020 garage sale on ebay. Also extrusions are heavy and will not be cheap to ship, be prepared for this cost. Speaking of cost, the brackets and nuts & bolts will add up quickly. Go over the amount you need and then double and triple check your numbers.
I would recommend using gussets, as opposed to angle connectors whenever possible. I would use gussets (at a bare minimum) for your connection of the gantry to the bearings. In fact, I would move the gantry to the bearing that is on the opposite side of the spindle. I know it's here because you are spanning both bearings with that angle bracket. I think you may need to re-think this connection.
These are just my opinions as I am definitely not an engineer. But I have been reading these forums for a couple of years.
Good luck
I understand what you are saying. the connection of the gantry with the bend factor of the extrusion itself might make a problem in the movement of the Y-axis back and forth. According to my calculations If I used steel brackets the motion should be smooth and the gantry risers will be stiff enough to carry the gantry. If I go down to the linear slides with the gantry I will loose most of the Z-axis movement. However, I hear you and that's why I am posting this thread. I will work with the steel brackets and tell you the results. Won't loose anything if I tried and failed :), well actually I will loose a couple of steel brackets. If it failed I will go back and lower the gantry to move directly on the linear slides. If not then we have learned something new
Also, may be the photos is not showing enough. but there is a lot of adapters between the linear slides and the extrusions that are running along the length of the extrusion on the gantry & the Y-Axis slides . They act as support for the extrusions too (stiffing them up more) currently debating to use steel or 6061 AL for fabricating them.
Note that my Y-Axis is the single middle screw & my X-Axis is the gantry
Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
pippin88
A single middle screw on a moving gantry machine is just not adequate in my opinion. Far too many problems.
Thanks for your input pippin88. I based my design on other designs, which I saw working and all were made with one central screw. I agree that 2 screws will for sure be better but the single middle screw if made right will work great and give the precision that I want working with wood and aluminium. What is the exact problems that you think is major?
Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
LeeWay
This is looking good.
I did build my first router with a center screw, but you have to build in adjustments to put pressure on the X bearings in order to eliminate racking. That and spreading the bearings as far apart as possible with help.
That said, I would not do a central screw design again. Putting a screw on each side of this design will considerably reduce gantry weight and double the strength to move the gantry. It does add cost, but I think the benefit is there to make that worthwhile.
Yes. I see that a lot of members here are not fan of single middle screw. I understand that having 2 screws will be better. but according to my design here the gantry is heavy enough to put pressure on the bearing. This is my first project in CNC machines and I guess I need to learn more from all your experiences. I am some how confident of this design after I have did some motion studies. However, doing computer simulation is not like real deal.
I would appreciate you keep an eye on this thread to see the results or the failures :)
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Re: 3-axis CNC Machine Kit - Model 1100X
Here is the extrusion selection for each part of Model 1100X. May be this will define more why I went with the design below.
The Main Frame: (40-4080 & 40-4012)
Attachment 232842 Attachment 232844
The Risers of the gantry (40-8080)
Attachment 232846
The Gantry (The beast 40-8016)
Attachment 232848
Re: 3-axis CNC Machine Kit - Model 1100X
A centre screw works ok when cutting in the middle of the table, however when cutting out at one side (one end of the gantry) there is racking, where one end of the gantry gets pushed further along the bearings than the other. Basically if you push on the front of one end the gantry will move relative to the other. Wider spaced bearings will reduce this but not eliminate it and means a smaller cutting area.
Another problem is table rigidity, which is much harder to achieve with the centre screw as you need the beam underneath. You can easily name a much more rigid table if you don't need this.
I've built a centre screw machine - never again.
Other than the centre screw, I think your basic design principles are good - you've used thick gantry uprights (most people still use thin plate).
The other thing is, if you can at all afford it, is to use profile rails. I haven't bought from them but BST automation on aliexpress have very cheap hiwin rails, other cnczone members have recommended them.
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Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
pippin88
A centre screw works ok when cutting in the middle of the table, however when cutting out at one side (one end of the gantry) there is racking, where one end of the gantry gets pushed further along the bearings than the other. Basically if you push on the front of one end the gantry will move relative to the other. Wider spaced bearings will reduce this but not eliminate it and means a smaller cutting area.
Another problem is table rigidity, which is much harder to achieve with the centre screw as you need the beam underneath. You can easily name a much more rigid table if you don't need this.
I've built a centre screw machine - never again.
Other than the centre screw, I think your basic design principles are good - you've used thick gantry uprights (most people still use thin plate).
The other thing is, if you can at all afford it, is to use profile rails. I haven't bought from them but BST automation on aliexpress have very cheap hiwin rails, other cnczone members have recommended them.
pippin88,
very comprehensive feedback. Thanks. The design concept below is very versatile. If you look below you will find that the Y-Axis is separate on a thick 40-4080 piece of extrusion. Adding a second screw is a matter of unscrewing the middle screw extrusion from the main frame which will remove the screw, stepper and everything related as one piece. Then I have to place this one piece axis to the left of the table and just create a similar one piece access and screw it to the right of the table and voila, you have a dual screw machine.
For the regidity of the table, my bad I didn't include the drawing with the MDF bed removed. There is a piece of 40-4012 in the middle to support the bed. I can add as many as I can to support it.
I will check these guys on aliexpress.
Here is a more detailed photo
Attachment 232892
Re: 3-axis CNC Machine Kit - Model 1100X
Center screw vs two screws. I have not doubt that two screws will keep the gantry more perpendicular than a single center screw, provided you don't loose any steps. I am curious as to if you use 2 home switches, one for each screw.
I think that what you cut and depth of cut will affect your success with using a center screw. Also the width of your X axis. Mine is about 24". I'm cutting wood and the largest end mill is 1/4" so my depth of cut is usually 1/8". So far, all has worked well. My home is in the left corner closest to me, so this is where I seem to do most of my cutting.
Again, just my opinion.
Rick
ps. I cut some small joints on my machine today and they came out really nice. I'll post some pics on my build thread.
Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
RicknBeachcrest
Center screw vs two screws. I have not doubt that two screws will keep the gantry more perpendicular than a single center screw, provided you don't loose any steps. I am curious as to if you use 2 home switches, one for each screw.
I think that what you cut and depth of cut will affect your success with using a center screw. Also the width of your X axis. Mine is about 24". I'm cutting wood and the largest end mill is 1/4" so my depth of cut is usually 1/8". So far, all has worked well. My home is in the left corner closest to me, so this is where I seem to do most of my cutting.
Again, just my opinion.
Rick
ps. I cut some small joints on my machine today and they came out really nice. I'll post some pics on my build thread.
I am guessing that one home switch will be enough either on the left or the right screw and that's my guess. I saw alot of center screws cutting 3/8 aluminium and using 1/2" end mills. They are also using smaller extrusions and 1/2" aluminium brackets. I am using bigger extrusions and 3/8" aluminium brackets and some 1/2" steel brackets (still questioning the use of steel) after I saw a lot of youtube videos with center screws and cutting thick aluminium very cleanly. The design here is 1100 mm for Y-Axis with 1000 mm cutting capacity & 800 mm X-Axis with about 650 mm cutting capacity (about 40" by 25" cutting capacity). Remember my y axis is the long axis.
Let's see as my goal is cutting aluminium more than wood.
Plan it, build it, try it and then modify it if necessary and that's my way. I know that I must do some fine tuning at the end and that's why the design here is modifiable even after the 100th cut.
Will check out the joints that you have done Rick for sure.
Re: 3-axis CNC Machine Kit - Model 1100X
With dual screws, you will want two home switches as well. This help to insure that the gantry stays parallel when homed. I have it setup that way on my plasma cutter. It has about a 5' gantry. It rides on skate bearings, so not quite as stiff as your project. Even after all day of cutting, it will home the gantry and hit both switches at the same time. It comes off the switches parallel. Nice insurance.
A center screw can be made that has no racking. Mine doesn't and there are many here at the Zone that do not. Several ways to achieve that even on larger machines. Larger machines have the screw size and length to contend with as well.
Re: 3-axis CNC Machine Kit - Model 1100X
There is a cable and pulley system method for curing the single screw racking issue. Many builders here and on other sites ended up using that, and it's inexpensive to implement.
Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
CarveOne
There is a cable and pulley system method for curing the single screw racking issue. Many builders here and on other sites ended up using that, and it's inexpensive to implement.
Good to know that. Do you have a link or can you give more details about the cable and pulley system. This is the first time to hear about it.
Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
LeeWay
With dual screws, you will want two home switches as well. This help to insure that the gantry stays parallel when homed. I have it setup that way on my plasma cutter. It has about a 5' gantry. It rides on skate bearings, so not quite as stiff as your project. Even after all day of cutting, it will home the gantry and hit both switches at the same time. It comes off the switches parallel. Nice insurance.
A center screw can be made that has no racking. Mine doesn't and there are many here at the Zone that do not. Several ways to achieve that even on larger machines. Larger machines have the screw size and length to contend with as well.
I guess I will try the middle screw and see how it will work. If it troubled me I will just buy a new screw and a piece of extrusion and make it dual screws. Good that you mentioned that we need two home switches. I didn't know that
Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
maly-miller
Good to know that. Do you have a link or can you give more details about the cable and pulley system. This is the first time to hear about it.
Here's one link that describes it with a drawing - cockrum.net It's called a moving knot cable/pulley system. Search the web and on CNC Zone to find more examples of it.
Re: 3-axis CNC Machine Kit - Model 1100X
Quote:
Originally Posted by
CarveOne
There is a cable and pulley system method for curing the single screw racking issue. Many builders here and on other sites ended up using that, and it's inexpensive to implement.
It certainly reduces the problem, but does not cure it.
To the opening poster: have a very good look at the costs. In a dual screw you need the two screws and two motors. However in a single screw you have the cost of the beam at the bottom joining, a moving cable system if you implement, often wider bearing spacing is required. My point is that these little things often add up, probably not to as much as dual screws but you won't save a full screw and motor cost.
With centre screw there is a big sacrifice in rigidity. You can't support your table in the middle.
Perhaps I sound too negative on single screw, but I've built a machine with round supported rails with a centre screw, with a gantry width of 2 foot (cutting width 400mm) and it's just not good enough. Racking leads to inaccurate cuts, and the table sags in the centre. So I like to help others avoid my mistakes / issues.