PRT Alpha

[bleeth]

Hi: I got a call from one of the folks at shop-bot today asking me how I was doing with my new bot Purchased in Jan. It was delivered in fine shape in Feb and by the time I got back from training was able to finish assembling it in March. It runs fine and dandy although I don't have nearly as much time to continue learning it as I wish with having to spend most of my weeks building furniture to pay the bills and my shop-bot lease. The subject came up re:alpha and I decided to share my thoughts with all of you. If I buy a new car in August I know that the new models are about to be released and if I am buying one that has major changes the salesman and company literature and advertising tells me so. Therefore my choice to buy a soon to be upgraded model is based on an informed decision. The very basic and major modifications to the next generation of shop-bot, on the other hand, were held very close to the chest by shop-bot. I understand from them that they are selling around 60 bots per month and I am sure that just as some of those recent buyers would just as soon wait for the upgrade, quite a few would have opted to go ahead with their purchase as the current bot fills their needs as is. However, that being said, I let the shop-bot rep (I am not a name thrower) know that I had a definately bad taste in my mouth due to the lack of being given the choice. I can't really say what I would have done as hindsite does not equal foresight but considering that the cost of upgrades means a huge cash outlay so soon after purchasing the bot classic as well as rebuilding or replacing the whole thing I for one will have a great deal of trouble feeling as good about shop-bot as I did a short while ago.

Dave

[elcruisr]

The problem is technology moves fast these days. When we buy a computer it's a has been withing a few months, so do we keep waiting for the next upgrade to buy? Vehicle technology is changing and improving every model year. Cell phones, you name it and they are in a constant state of techno change. This is even true in the world of CNC machines in any price range.

Shopbot IS a business and they have to compete against other companies all of which have various R & D projects going to out do the competion. They were trying to keep things quiet, I'm sure, because they where probably not sure IF their new technology was reasonably bug free and exactly WHEN it would be released because of the aforementioned. I picked this up from some people I talked to at Shopbot while discussing another matter.

If things had hit a major techno snag then the PRT Alpha might have suddenly been set back six months or a year. As a company that survives on it's sales that would have been a major nightmare if they had had us all primed and waiting for a release in a month or so.

I was satisfied with my PRT and I'm now running PRT Alpha #2. It had a few suprises up it's sleeve as any new machine will. Namely a learning curve for me. If I bought a Northwood top of the line machine today I fully expect the next model out will have more than I bought but so what? I bought it fully knowing what it could do, I'd still be faced with a learning curve and spent my money based on that.

Even if you spend the money on an upgrade you will still have less in it than any other comparable machine. If you don't, you still have a damn good machine that can turn you a good profit as I have with mine the last two years.

Eric

[erik_f]

I can't really say yes or no to thing about Shopbot keeping its Alpha design secret...I can say that knowone will be able to get a 4x8 machine up and running, with software, and have it usable for $8500 ever again. Looking into the Alpha a bit more...it really doesn't make sense to buy one without a spindle...the electrical hook ups required are (at least what I have seen) more costly to put in. I ran a quote on a new alpha with a spindle (I wouldn't want to buy one with out...it doesn't make sense to me) and the cost is $14335.00...thats close to twice what I paided for my machine. In some cases I understand that its not only about the money it cost for the upgrade...but the large investment in hours that it takes to put these things together.

Erik

[Brady Watson]

I guess it's all how you look at it.

No one says that you have to have a spindle to use the Alpha...You can just as easily use a Porter Cable router and keep your speeds within reasonable limits. Then when you get the $, upgrade to a spindle if you really need it.

The majority of the work that you are going to do on the Bot will fall within the speed capabilities of the standard PRT. Yeah...the Alpha is nice, but what are you going to cut at 10IPS besides foam? Even with the 5HP Colombo, I rarely cut any wood product over 2IPS, although jogging at a faster rate would be nice. It would also be nice to have faster speed on the plasma cutter.

If you think about it, the increase in price also makes the resale value of our regular PRTs go up. It will cost more money to get into a SB period.

Spend some time using the Bot that you have. You will see that you are probably not going to need the increased speed of the Alpha. Imagine your lease if you did get the Alpha with a spindle...probably a LOT more.

-Brady

[stevem]

The most valuable feature of the Alpha model is the closed loop feedback. Regardless how fast or slow you set the cutting speed, the tool will not lose it’s position and ruin your part if the stepper stalls.

Because the gear boxes are eliminated, I suspect the accuracy will increase somewhat due to elimination of slop in the gear boxes.

As for the value of existing PRTs, that is likely to decrease much faster than expected because the trade up to an Alpha is relatively inexpensive.

I would have gladly paid the extra $2000.00 in January, when I purchased my machine.

[erik_f]

The Alpha and the Classic are rated the same for accuracy. I would believe if the new model was more accurate that SB would advertise it...not keep it the same. I bought my machine less than a year ago...and I guess I accept the risk of being "cutting edge" ,and that is, your only cutting edge for about 15 or 20 minutes. I got what I paid for...and I have what they promised me. Customer service has been everything they said it would be. For me the investment is already made and now its about what I'm making and not so much what I'm making it with. No use crying over spilt milk. Resale? I didn't buy the shopbot to sell it...so sure its a concern, but not very much of one...by the time I go to sell the shopbot it will have paid for itself about 100 times at least. And if you guys are really that pissed...SB seems like the kind of company that could be guilted into giving you a better deal on the upgrade package now, just to keep you happy...who knows...its worth a try.

Erik

[elcruisr]

"Yeah...the Alpha is nice, but what are you going to cut at 10IPS besides foam? Even with the 5HP Colombo, I rarely cut any wood product over 2IPS, although jogging at a faster rate would be nice."

Wow, you can easily cut alot faster. I'm doing production work at 10"/sec single passing 3/4" plywood and MDF. You just need the right tooling and ramp tuning. No problem with the accuracy. The spindle is running well within it's temp and load specs.

We've got over 5,000 hours on our spindle and are finally looking at a bearing rebuild. With what I know about spindle care and feeding should get even more out of the next set.

Eric

[gerald_d]

If I was a first time budget CNC buyer today, like I was 3 years ago, I don't think that I would buy the alpha. I would try desperately to get a classic instead. A huge part of my decision is the ability to do my own trouble-shooting and repair with locally available components. The new Oriental Motor Alpha system is too specialised for me.

[Bill I. (Unregistered Guest)]

I purchased my PRT with a Colombo spidle in May 2003 and asked if they were going to make any major changes and if so I would wait to purchase my new ShopBot. I was told that no major changes were going to be made to the PRT. Now comes the Alpha just less than a year later. I checked on the upgrade cost and was told $3,995.00 because I purchased the PRT before January 2004. I was also told if I would have purchased the PRT in January 2004 or later the upgrade would be $2,000.00. Why must I pay more for the upgrade and why was I not told that the PRT may be going through some changes? I would gladly pay $2,500.00 for the upgrade but I can't justify $3,995.00. Can anyone tell me why I must pay $3,995.00 for the upgrade and someone that purchased the PRT in January only pays $2,000.00??

[richards]

Gentlemen,

Having been self-employed for 30 years, I've been through all kinds of changes from all kinds of companies about all kinds of things. Twice I've been burned by companies that have discontinued a product that I've spent countless hours incorporating into my business plan (anyone need Ampro products or Ziatech STD-32 boards?). However, as an outsider, my opinion of Shopbot is that good people are doing the best they can in a volatile marketplace.

Let's be very objective. Paying less than $20,000 for a machine that can compete with a machine costing ten times that amount, given a little more expertise on the part of the owner/operator, means that someone has found a real bargin, a real possibility for beating the competition. If the machine costing $20,000 can do five times the work of a machine costing $10,000, well, that's life; that's competition; that's great. If the company building the new machine offers an upgrade, even at $4,000, then where's the beef? I'll gladly sell you the $30,000 of Ziatech product that I have on the shelf that is totally useless because the company's founder was more concerned with his own bank account than the bank accounts of his customers.

Run a break-even analysis on your product. If the numbers show that the Alpha machine will make you more money, then buy machine or the upgrade; otherwise, be glad that you have the machine that you have.

Now, as a personal note, I've done the number crunching. The PRT 120-60 didn't meet my needs. The PrtAlpha 120-60 does. As soon as the mortgage people finish their paperwork, I'm going to place an order for the PrtAlpha 120-60 because it is a good business decision, not because it is the newest, latest, greatest model. (Hoping all the time that the learning curve will be reasonable and that there will be enough business to support a machine that runs 5 times faster than the older model.)

Basically, the conversation about sour grapes should be left to the people who spend their lives sampling the juice of the grape rather than doing something productive. If a machine/tool makes economic sense, then buy it; otherwise, be grateful that you didn't need the latest, greatest, newest CNC machine.

[weslambe]

When the Alpha came out I was:

RED then
Green. now I'm just
Blue.

Wes

[ron brown]

Gentlemen and less,

I agree with Michael on "it should be a business decision". One of my first comments on seeing the Alpha was, "I went through about $500 of bits learning on an old cable driven machine, I'd bet it would have gone up to a thousand with the Alpha." That thing moves fast enough to make a spacebar hit near impossible if it was a case of, "Maybe that screw is a little close?"

I do know the development of the "Alpha" was very fast. Last Janurary there was still talk of "tweeking" the PRT boards for a little more speed. If the Alpha had been solidly in the works, "tweeking" to go from 2 ips to maybe 2.5 ips would not have been a question worth working on.

Personally, on my machine I normally cut at 1.5 isp. I can cut more parts than several folks can assemble in the same time. When I worked alone, I would start the machine and assemble while 10 minute parts files ran. A machine that runs as fast as an Alpha would have mandated me to watch and change parts.

If one really wants to build an inexpensive CNC machine, it can be done. It can be done for only a few thousand dollars - and a LOT of time. It takes a diverse range of skills not normally held by one "fool". If the person choses the wrong controller and motors they can really be "on their own and in left field." This would be compounded by the lack of support other CNCs have an abundant supply of.

The ShopBot, whatever model one has from cable to Alpha, gets support from other ShopBot owners. It is a machine capable of producing accurate parts and keeps improving.

BTW - if you really want an inenexpensive CNC - see if you can talk YUGO into going into the business.

Ron
Ron

[fleinbach]

It all seems clear to me guys. If you want or need a machine like the Alpha, buy one! That's what I did, once I realized what an incredible and indispensable tool the Shopbot is. I did this even though I had just purchased my PRT96 in Aug 2003.

I was introduced to the shopbot 3 years ago while visiting a friend who was making curved trims for local builders. He said he paid around $3,800.00 that seemed like a very reasonable price to expend but I certainly wanted to be sure I would have enough work to justify such an expense. By the end of 2002 I was making a lot of curved parts with a router for theater rooms I designed. This was becoming very tedious and time consuming as you all know. So I found I had a need and called Shopbot to purchase one. When I found out the price had gone up and I was going to have to invest over $6,500.00 for one I almost changed my mind. But I finally decided it would be a good investment and purchased the PRT96. The only mistake I made was not getting a larger one since I use quite a few 61" X 121” sheets of MDF. Had I called Shopbot today and found out I would have to spend over $10,000.00 I'm not sure I would own one. But now that I have used one I am upgrading to the Alpha PRT120 with a 3HP spindle. I decided to make the purchase before selling the PRT96 because I use it several times a week and can't be without one right now.

I made the decision to purchase the new one because, One I needed a larger one and two I am sure there are plenty of people out there who will purchase my PRT96 because they want to try one but can't quite justify the price of the Alpha. Plus they will be more then willing to purchase a slightly used one that will produce parts exactly like the more expensive Alpha. Not everybody needs the speed, not even me, but I am one of those people who just have to have the latest. My other passion is for electronics and I wish I could recoup the Hundreds of thousand I have spent over the years on the latest computer, LCD TV, DVD player, VCR, Satellite receiver. I always have to have the newest available. Tools seem to be another story though. The resale value on tools can even increase from there purchase price, so I see tools as an investment.

[danhamm@abccom.bc.ca]

Hello Guys and Gals..I sold my bot about 2 yrs ago..and will be ordering a alpha, soon as our canadian dollars..peaks..its at 77.32 right now
maybe won't go any higher..hmmm. I was wondering if there were any curious perks with the new alpha..that havent been posted abnormalities..
software or mechanical.. cheers...Dan Hammerstron

[billp]

Dan
Welcome back!!! I just upgraded my PRT to an Alpha and I'm trying my first cuts today. I'll keep you posted on anything interesting...Bill Palumbo

[paco]

At the moment, the control software do need some fixes... as for the Alpha though... but, it's going the right way! The manuals about Alpha particularity do need to be update... such things like; you need all the motors pluged to test first X's (just disengage'em), if you plan to use the installed router/spindle relay/contactor, you need to know that you will have to added a SO line to all your file... manualy... as the control box will power this relay/contactor only if thoses line are present... You might like to know, if you plan to use a router, that it is suggest to get a 3 conductors wire to your control box; one to power the control box and the second to power the router relay/contactor... some functions are not yet operational like converters, some routine files do need some modifications (as for my purposes though)... System variable have change in Alpha control... As for mechanics; even claim of not, the X carrier have needed to be squared, Y carrier have needed to be squared and shim the rollers to get'em rolling all on rails... The channel nuts provide to mount the Z are not really fun to deal with (regulars hex would have been better!!!), hold down rollers on Y carrier were not really well set (much too thight and not siting right... Suggestion to installed the Z on "first hole" was'nt good for me to clear height area under X carrier...

That's some of my observations... there's other which I just don't remember of but still it's a great, GREAT machine... and it's Fe-Fe-Fe-FAST!!! 8-)
PS: Probably that most of this have been fixed now...

[jsfrost]

Paco,
I've been wondering where to put my list of minor gripes, mostly those you listed. Adding the SO,1,1 lines is a pain, especially for those learning or doing one ofs. And I really think the router should kill on a panic stop. And even after you exit the file after a spacebar stop and the router's off, the next MZ,1 turns it on again.

Jim Frost

[paco]

I don't use this device... Is'nt "killing" the router as you use the PANIC???!!! And is it really ON again only as a M command is input???!!! Very strange... Keep us inform of your observations Jim. Thanks for sharing!

[ted]

Hi Jim and others,

On the issue of SO 1,1 and control of the router/spindle. We spent a lot of time working through how this should function to both be convenient and safe. We settled on a system that offered 2 options:

1) You can generically indicate to the software that you want to run the router in moves and files. You do this by turning the #1 output on, using either the yellow keypad (click the #1 switch) or by giving the SO 1,1 command from the keyboard. Now, whenever you run a file, the file will pause at the start and you will be prompted to start the router with the 'Start' button on the Control Box. When the file ends the router will be turned off. With this method, the #1 output will still be active at the end of the file, so the next time you run a file you will again be prompted to hit the 'Start' button if you want to run the router.

2) You can also indicate to the software that you want to run the router by placing the SO 1,1 command at the start of a file. In this case, the output activation is local to the file and can be turned off at the end of the file with SO 1,0 [we are considering making the turn-off automatic within a file]. If you want to use the router with a subsequent file, you will need to put an SO 1,1 in it, or use the first method above.

In all cases: Ending the file will shut down the router. Stopping the file from the keyboard will shut down the router. Hitting the E-Stop will shut down the router and require a "Reset". The idea of this sytem being that the software can turn off the router, but not turn it on unless you have hit the 'Start' button to indicate that you are turning control over to the computer.

I might also note, that we are updating the post-processor for PartWizard so that it automatically adds the SO commands when the Part File is generated ... removing much of this little hassle (the post should be available on the web site shortly).

All that said, Jim, I think the problem you describe with the router coming back on must be a defect on the control board. We'll send out a new one to you Monday morning. Yours should be working as described here.

-Ted

[ted]

To All,

After I replied to Jim above, I looked back over this thread and noticed a couple of questions that no one from ShopBot had yet commented on. I thought I might add my 2 bits here.

On the question of whether you need a HF spindle (rather than a router) with our new PRTalpha tools
--------------------------------------------------------------------------------------------------------------------------

We do expect that we will sell more HF spindles with PRTalphas than we did with PRT tools. This is because with a spindle, higher cutting speeds can be achieved and the high quality tooling designed for spindles will function very efficiently. With PRT tools, we sold a reasonable number of spindles. The choice of a spindle was made to achieve more cutting precision (spindles have less run-out), to have less noise in the shop, and to get longer production life from the motor. Both spindles and routers were limited to cutting speeds of about 2in/sec. So with out earlier tools, speed was not one of the reasons for purchasing a spindle. Now, with the PRTalpha speed adds to the rationale for why one might buy a spindle, but the PRTalpha certainly does not require it.

Depending on what you are cutting and the type of tooling used, the PRTalpha will allow cutting with a router at speeds from 2-6 in/sec (that is, up to the speed the router starts to bog down). This is not as fast as the 10in/sec cutting that the PRTalpha can deliver with a spindle (depending on the material, of course), but it is still pretty fast. Moreover, you are able to rapidly position with either the router or spindle at 30in/sec. Because there is a lot of positioning motion in any cutting file, just being able to jog rapidly offers quite a production efficiency advantage for these tools, even if only a router is used.

Just as a note, a spindle can always be added to your ShopBot at a later time. But if you think you might want to add one, let us know when you are ordering a PRTalpha so that you can get a control box with the heavier contactors that will be needed for switching the higher spindle loads rather than having to add them later (and needing to send the box back to us for the required change).


On the question of purchasing a PRT in the period before the PRTalpha was unveiled
-------------------------------------------------------------------------------------------------------

For some, I thought a little history related to this question might be of interest.

It has been pretty well known and shared with our customers that for the last several years we have been trying to improve the speed of our tools (until now, speed has been the biggest compromise in affordable CNC tools). As of early last fall, we had developed a new control board and drivers that we believed would yield a 20-30% increase in speed (along with a more industrially compliant control box). We were getting ready to start seriously field-testing these control boxes and planned to potentially introduce them in the beginning of 2004, along with some of the stiffening and rigidifying improvements to the ShopBot carriages that you now see in the PRTalpha tools. While significant, these were not radical changes and would have gradually been phased into production. The improvements, along with other pricing pressures due to the economy, would have resulted in a 10-20% increase in cost of PRTs in 2004. At that time, we were thinking that a 20-30% increase in speed sounded pretty good.

About this time, we were approached by Oriental Motor with regard to the possibility of incorporating their alphaStep motors into our tools. Oriental has been selling these motors (actually a motor/driver system) for about 4 years, but because of the relatively high retail cost, we had never considered them. [Oriental makes great motors, and none of them are cheap.] More out of curiosity than anything else, we put a sample alphaStep on one axis of a PRT and took a look at how it performed. We were blown away ... and life around ShopBot has not been the same since ... incredible speed and smoothness, and a closed-loop system to boot.

We spent the late Fall and Winter, working with Oriental to see if these motor/drivers could be adapted to our multi-axis CNC application (they are primarily used in standalone automation applications). This process involved a lot of testing, puttering, and Oriental's modifying of the drivers for our purposes. In case it may be of interest, the motors/drives were actually developed by Oriental's American research branch (Seiberco) and were originally known as 'sensorimotors' because the positional feedback sensors are built into the motor itself rather than attached externally (as for many servo systems). The logic behind Oriental's approach to the motors is to take the best of steppers (their power for short quick moves and their robust simplicity) and combine that with the feedback advantage of servos. Even though the alpha drives are very technologically sophisticated, they are less complex than servos and require a lot less tweaking. This also means that, for equivalent power and speed, the alphaStep can be considerably less expensive. It this performance/price advantage that has convinced us that alphaSteps are right for ShopBots.

Now back to history ... at the end of January we made an initial decision to go with alphaSteps and settled on pricing with Oriental. At this point, we had tested them on tools locally, but did not have any prototype tools at test sites in the field. Field evaluation was the next step before finalizing production plans. The field tests were impressive. We moved forward and we showed off the first of the PRTalphas at the ShopBot Jamboree here in April. Then, during the Spring months we worked at a fast pace to get the new tools ready. We started shipping ShopBot PRTalphas in June and over a hundred have gone out the door already. So we started with the idea of a 20-30% improvement in speed and an obligatory 10-20% increase in price. We ended with a 1000% increase in speed (that’s 10 times faster), closed-loop reliability, and a 20-25% increase in price ... and with a new, radically high performance, yet still affordable CNC router.

We pushed the new tools into production quickly, simply because we wanted to minimize the time from when we put a new tool in development to when it was available to our customers. As noted in the posts above, having a new product coming along makes for an awkward transition for those in the process of buying. We handled this as best we could. Shortly after our decision to go ahead with the tool we let all potential customers know. For those who purchased during the Spring, we offer an upgrade price that is only slighty higher than the difference between the cost of the old model and the new model (and probably below our costs). That is, we tried to create a situation where there was not a penalty for purchasing too early for the new model other than having to install the new motors and control box at a later time. For those who purchased a little before this time, we also offer a discounted upgrade price.

Perhaps most importantly, we are committed to keeping older ShopBots running and productive. We offer an upgrade package for all PRT ShopBots to give them PRTalpha capabilities. When the cost difference between an older PRT and the PRTalpha is taken into account, along with the fact that the older tool has been producing revenue for months or years, and that the upgrade essentially makes this tool new again, these upgrades are very inexpensive. We have worked hard to keep our tools priced as low as possible and those who have visited us here in Durham will probably attest to our clear efforts to keep our products straightforward and affordable.

At ShopBot we invest considerable effort in development of new tools and new software. But recognize that only a few of our development projects actually make it to the product stage and it's hard to know what will be a new product until the production decision is actually made. We will continue to innovate to remain the leader in affordable CNC, and we will continue to do our best to insure that new advances can be adapted to earlier versions of our tools.

Well ... perhaps I should get off the soapbox, but just wanted to fill you in on how the PRTalpha evolved.


-Ted

[paco]

I really like when I can get Shopbot staff point of view... Thanks Ted for sharing thoses info about the machine that I use... and that Shopbot TEAM built.

[sbyrne@swingdesk.com]

I just want to say that I've been shopping my company's first cnc router for a few months and have spent probably 50-60 hours hearing people push their products, researching features, options, production methods, tooling, etc. I have enough $$$ for a more expensive machine like a Komo, but want to keep my footprint small with a moving gantry. Having researched these machines I am very impressed with the PRTalpha. I've heard nothing bad about Shopbots other than the pain of assembly. More than anything I am impressed by the existence of this forum and the quality of information it provides. The thread from Ted on the history of the alpha is superb and combined with everything else, helps with my decision a great deal. Thank you all for your inputs!

[beacon14]

If money is not an issue, then have ShopBot assemble the tool for you. Problem solved.