#241
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A router design is just not there to replace big iron milling machine center.
However you do it it can't be perfect. If you must do it, at least use real rectangle rail & carriage for best rigidity. U did mentioned poor quality wheels, did you machine them yourself? |
#242
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I own the 4 systems and I can compare SBR, TBR, Linear guideways, and I use also Hepco precision forged and machined Vgroove rails and bearings, which I belive represents the next level compared to the standard Mechmate's V rails, made with the skateboard. They are more expensive than an SBR20 system, but not as good as a SBR system. The lateral load is not as good, and you need a double V-rail in opposition to realy limit a movement on an axis. I mean, like the Z plate of the mechmate, some V-bearings on each side. The MechMate principle counts on the weight to manage the rising force. The SBR stands between the V-groove and the Linear guideway system. According you compare the best quality of each system.
Marko, the best machine possible means always an expensive machine. Quality and money are always linked. From linear guideways to servo motors. I talked about TBR, because their profile is lower than SBR, and the mounting surface is larger. Two reasons to choose TBR when it's possible. |
#243
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Again here is the overall problem. V-rail, shaft linear and profile linear rails are all designed for compression load. When machining wood, the uplift is minimal compared to metal so most of the load is compression. The exception would be the capture of the Z axis. It does this fairly well even with only using radial bearings.
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#244
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@Ken
No I did not make them myself, as if I did, they would be much better done. And I can go to rectangular linear guides, because that cost a lot more. I dont understand this one thing. Everybody says go to this solution, and all are fleeing from SRB20 linear guide. If I use 10 mm round linear guide it would still be better then these V groove rails (like Axel said) V groove is lowest possible rails, and if I'd compare this with cars, these V grooved rails are a carriage and SRB20 are VW passat CC. I am not trying to build a perfect machine, and with all the money in the world, there are no such thing as perfect, but this will be MAJOR improvement, in stiffnes, in precision, in quality, in reliability. |
#245
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It is all a subjective weighing scale decision process.
You balance the subjective/objective pros and the cons, and even than, when the result says left... you can still decide to go right. I merely mean that for me personally round linear rails require all the prep you have to do for straight linears and already a large part of the costs. If I am not happy with the V-rails (to be decided) I will go straight for the SKF rectanugar linears which I bought for the same(!) money as you bought your round ones. Yes, they can be found used ( and mine are not worn I might add) for small money as well. I am with Ken, that the MM is good at what it does, and does not incorporate the rigidity of a metal CNC, but when you adapt speeds and feeds, and spindle, can still be used to machine metal. But.... if you mostly cut 300x300 mm size objects to high accuracy in metal, your better/quicker/more economic solution would be to adapt a rigid manual milling machine to CNC. Having said that tinkering is good and I follow your thread with great interest. Last edited by Fox; Thu 13 March 2014 at 04:22.. |
#246
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The MechMate was engineered to beat the expensive ShopBot One, at low cost, with ordinary tools, skils and knowledge. And that was a succes. The MechMate do pretty well it's job : cutting wood and/or pannels at a good speed, and much better than some can say. It can make an reasonable plasma cutter, even if it's not necessary to build that heavy for this job. In my opinion, the MechMate is not born to be a metalworking machine. Those are pretty different in many ways, it's not just a question of rails. Anyone can modify the guides and other stuff, to cure some problems, but it can't be a good production machine to make money on machining metal parts. Eventualy for grooving aluminium sheets, but not engineered or metal parts. You will cure a problem to discover a new one. You talked about cars, so can transform a city car to transport concrete bags, but it will never do it as well as a truck, and certainly not for the same life time. I know it's not what you wanted to hear Marko.
Last edited by Axel1966; Thu 13 March 2014 at 07:05.. |
#247
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We are not beating on you. We are trying to normalize your expectations. I work on mills, lathes, CNC mills and lathes. There has to be a consumable part to wear and the bearings are not meant to be that part. They are precision placement. You will require gibs for a long lasting machine for cutting metal. Replacing with profile linears (what you are calling rectangle) or round linears I fear will not give you what you are hoping for. Only a higher repair cost.
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#248
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Marko, I am planning to build a MM in Hungary. May I ask you where did you order the laser cut and bent parts?
many thanks, Andras |
#249
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Marko,
Did you make the upgrades you were planning on doing? |
#250
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Looking at images on the first page, all I see is advertisements from image shack. ... Bummer.
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#251
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Hello Pete and Jack.
I have made all the upgrades to my machine. I installed 20 mm shafts on all axis and my machine is now very rigid. The calibration was done in matter of 2-3 hours, unlike V groove rails which were pain to modify. I still havent installed liquid cooling, but that will be done in a week or two, and have been cutting aluminium with 1 mm stepdown in 20 mm/sec and all my cuts are pretty good and quality. Only thing that is bugging me now is rack and pinion which is very low quality and I can feel the vibrations transferred to end bit, but its very very small, and not like before. There is always room for improvement, but I am very satisfied with machine, and will plan to make a reduction 5:1 in the next few months. I could be moving to a smaller machine, duo the fact that my workshop is smaller and machine is to big and I am using 40 % of working area. Here are some photos of the machine and you can check my progress on my facebook profile @Jack: I would nee to re upload whole progress, but you can check here full prgoress: lopataos.blogspot.com https://www.facebook.com/maister.cnc |
#252
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Great to hear from you. I am glad things are working out. Do you have any pics of the upgrade process?
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#253
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Wow! it looked heavy. after the heavy-mod.
10:1 bear box seems like a must. You should has went straight to CNC-fy a knee mill in the 1st place. Last edited by KenC; Mon 27 October 2014 at 07:06.. |
#254
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Marko
This upgrade means, better precision? Thanks. |
#255
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Wow! ... Thanks for the updates!
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#256
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Hello guys,
I was trying to beat the clock, I was working all day doing the upgrade, and did not take any pictures. @Ken: 5:1 would be plenty of resolution, and would still have the speed of 120 mm/sec to wooden parts. @Leo: Precision is much better, no more vibrations and pretty stiff machine. Al thou, machine is a bigger then I need it to be. With new rack and pinion, I would not even see the tool marks on aluminium, which are now pretty small. @Jack: no problem. I guess I lost my account pictures and will post here or on Facebook. I'm moving in aluminium and titanium cutting, and completely moving into bicycle business. Here are some pictures: |
#257
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So that whole part was machined on you MechMate?
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#258
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You guys with Facebook accounts really should send Marko a friend request.
He posts some serious cool pics of bike parts there. |
#259
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@Mike:
Yeah, whole bashguard was made on my Mechmate. How do you like it? But that was cut on low quality end bit. I am trying to some Datron or Iscar end bits, they are by far superior end bits for aluminium. Feeds and speed are 200% then regular, and finish is industrial. Precision is pretty high and vibrations are really low, so I will give it a go to machine Titanium Grade 5. @Darren, thank for inviting people on my facebook page. This is my company facebook profile: https://www.facebook.com/shovelbicycleparts |
#260
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Hi Marko,
good stuff that your share the upgrades, and nice to hear it was worthwhile. You are cutting nice things ! I am impressed with the speeds you seem to be cutting at. Are you willing to share some of the parameters and the bit's you are using ? I am just cutting woods now, but am looking forward to some alu experiments soon. It seem to me you are tumbling all parts after cutting, to get a better finish, right ? If I we're you, with all your experience in alu, the first thing I would cut right now would be some nice gearboxes from aluminum, 3:1 or 4:1 be fine ( I am using 4:1 myself ). That will improve things significantly ! Ps. Why did you mount your rack teeth pointing upwards ? It's a dust/debree magnet that way ? Last edited by Fox; Tue 28 October 2014 at 10:34.. |
#261
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Hi Fox,
The tools I am cutting with is Iscar tools 4 mm single flute carbide end mill which I got from a friend, and he orders it for me, I cant find you a link. Another end bits I am using and are also very good is Datron end bits. http://www.datron.com/ single flute. They are also pretty awsome, although they cant compete with quality of iscar end bits. With iscar end bits, I am cutting with 1 mm stepdown with around 20-25 mm/sec @12000-15000 RPM ( belive in 1 point I was going 30 mm, cant recall for sure), and cutting is pretty silent. As I was doing some stuff the other day, and got my clamp somewhere stupid, I broke my iscar end bit and I cant make a video how its cutting. I have some iscar 3 flutes en bits, but they are designed for harder alloys of aluminium, and with much greater speeds (something like 50 mm/sec with 1 mm stepdown) and im still afraid to use them. Or even better, they are deisgned to use with 10 mm stepdown, and with 1 mm stepover at 20 mm/sec. Mounting my rack facing upside was because my spring were pretty weak, and when I got vibrations on my old system, rack and pinion tend to split apart, which cost me a vibrations and lost steps. In this way, weight and spring are pressing motor on the rack and its pretty solid build. only thing is my alu debree is finding its was to the rack. I will manage that with some liquid cooling and a little plastic on Y slide to act as a cover for debree. Fun part will be cutting Titanium Last edited by marko cro; Tue 28 October 2014 at 10:58.. |
#262
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Hi Marko,
Thank you for that info ! I know of a little trick that I saw on a commercial machine which has rack pointing upwards: They make two rollers ( with bearings ) on either of the machine axis. Then take an industrial quality belt. Fasten one end on the gantry, go over the roller on one end (left for example), round it, then all the way back to the roller on the other end (right for example), round it, then attach to the gantry again ( other side then where you started). You've created a loop around the rack. When the machine moves, the belt will follow, and the rack is always covered. Last edited by Fox; Tue 28 October 2014 at 11:21.. |
#263
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Wow, cool work on the Facebook page Marko. I assume your machining the carbon fibre on the MechMate too? Are you also doing your own anodising? And those handle clamp bottle openers are they before stiffening mods or after?
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#264
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Hi Dale,
Yes, I machine also a carbon fiber, but they are pretty easy to machine, with proper tool. I am also doing all by myself anodizing of my parts and I have achieved some pretty good results. I don't think I understand the question, can you rephrase it please. Also, those bottle openers did not get anodized properly, due the some iron in aluminium 6062. Additionally, I have purchased a small tumbler and tumbling parts alone. I have given 3 years of my life for this, and I like how it goes so far. I am glad you like it. https://shop.vhf.eu endbits I was talking about. Not Iscar. Marko |
#265
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You answered my question I was looking at the bottle openers and thinking the finish was not as good as some other parts and wondering if you made them before you performed your stiffening and rail modifications to your MM.
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#266
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Long time no see
Well, here is some Titanium (Grade 5), tough cookie to chew. But not for my MM. I am cutting 0.3 stepdown with 15 mm sec, or 0.5 with 12 mm sec, and that was tested without cooling liquid. With cooling I would dare to go 0.7 SD with 15 mm /sec. This chainring still needs some machining, but that will come tomorrow. Nothing is imposible. |
#267
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Woaw....nice...and impressive (for me) !!
To say....lately on my side I'm having a had time with simple....Baltic birch ply |
#268
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Thank you Robert.
I was pleasantly suprised with end bits and rigidity of my machine. What seems to be your problem with machine? Marko |
#269
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Hi Marco....
I'd say it's many little details of witch, one on one by them self would go through unseen or unnoticed, but since I move my beast to it's ( & my) new home, it's not the same. I have to find time to give it a total inspection not to say refresh. For work that need additional hand (or machined) attention, it's perfect, it does the job quite fine, but for detailing & having a nice finish....say like engraving.....or as you did......not quite there anymore Nerver the less....I'm still VERY please, but it's due for a good check up & fix up...That all...I think Later |
#270
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Nice work. I have another question. When you fixed your linear rails, did you level your beams with epoxy? Or just shimmed around each bolt in your linears with the ibfamous coca Cola cans?
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