Originally Posted by
lgalla
Digits
Jacking up the corners may prove more difficult to acheive alignment.If jacking up is to save money,the extrusion is cheaper than the filler.Usually one might start with the base.I would recommend building the whole machine first,confirming the alignment of the linear rails,then finally doing the pour.We don't want to end up with an expencive "patio stone"If using 80/20 for the gantry,the larger voids are a perfect candidate for Epoxy/Granite.I had investaged 80/20 before and determined it's not a good machine material,but with E/G it becomes attractive.
One thing might I ask?From previous posts are you talking about water based concrete or polymer concrete?On this thread concrete is concrete,polymer concrete is polyester resin & aggregates and E/G is epoxy/granite or quartz.The first two are worthless to us as neither will stick to aluinium.
Larry
I'd have to say this sounds the best so far Larry, I've been doing my share of leveling structures of late and know that its not as easy as it looks. Plunking a pc of steel [or 80/20]into the btm of a mold doesn't dictate accuracy in any way. Infact it makes it harder. How are you going to get the two pc's sqr/parrallel and planer? Pretty tough I'd say. On the other hand, using your melimine form and a pre fab'd 80/20 structure [ even if its lightly connected] is going to give you a fighting chance at getting it planer and parrallel. When using a form of this type, you don't have to worry about draft or getting the 'part' out of the mold as you would take the mold off the part instead. If you were going to make several of these, you would need a two pc mold which can be re-assembled [ not as easy as it sounds]
My two cents.
Jerry [ someday I'll build a mill like this, after I get my current mill build completed ]
JerryFlyGuy
The more I know... the more I realize I don't
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)