Setting up your PRS

[dray]

When I set up my PRS I fount alot of stuff was cut out of square. So it took me 2x as long to set up my PRS because I had expected things to be cut square, then had to trouble shoot all the way down the line to find the problems.

The Extruded Aluminum on my X-Car was cut out of square on both ends and It caused huge havoc in my life because first off I didnt know that was he problem then looking through the manual I didnt have an easy solution to square it up properly.

There were directions to do so but they would never get it accurate enough for me and seemed to me anyways to be a waste of time.

So I did it the same way I square and lvl things up on a daily basis.

I have had a quite a few emails and phone calls from reg folk like myself that arent Boing engineers so I made a simple easy to follow PDF file with some simple pictures that are easy to follow..

Hope it helps any other PRS users out there.

Attaced as a PDF you may need to save and change the suffix to PDF, unsure about board uploads they elude me.



squaring.pdf (http://www.talkshopbot.com/forum/messages/312/squaring-19593.pdf) (34.8 k)

P.S. Its nothing fancy, its just that it took me forever to find out where the problems were Hopefully I can save someone else a little time.

[srwtlc]

Hey Danny,

Thanks for posting that. I've been wanting to start a thread here on 'Assembling and Setting Up Your New PRS', but have been so busy that I haven't even had time to get mine completely set up and have to keep using my PRT.

I'll be checking the squareness as time permits this week.

One other thing I'd like to add is that when you plumb down, do so off the rails to check that the beam is perpendicular to the table also. I know that mine is between 0.625" and 0.125" away from perpendicular from the top rail to the bottom rail.

Some other observations or tips would be...

When putting together the table, check the legs for square at the face that will be bolted to the rail and the face that will bolt to the cross member. Assemble the table with the four best corners facing each other. If you have an out of square corner on one, when it's bolted up tight, it will cause the rail to bow and you'll have a tough time getting the v-rails parallel. I had to shim out the outside or back edge of one leg to get one rail straight enough. I could have disassembled and started over, but I didn't really want to have to do that. Also, and I think that this is going to be updated in the assembly manual, I shifted my rails 3" to one end so that I would have the same amount of overtravel on each end of the table. Instead of positioning the legs 6.875" in from the ends (per the table spec sheet), I put one end at 9.875" and the other at 3.875"

If your going to use a Porter-Cable router, you won't have enough travel to reach the base layer to cut the bolt holes for bolting it down (or even be able to reach the spoil board with shorter cutters while using three 0.75" layers) My fix was to move the upper limit stop bolt up as far as I possibly could without disengaging the rack/pinion. There could be a change coming for this, but the current adapter plate for the PC router places it too high in the travel envelope.

For me, the proximity switches needed to be set much closer that stated in the manual or they had a tendency to flicker on/off, making it difficult to move off them when setting up the homing offset or anytime I was on them.

I hope that these and Danny's tips will help those yet to assemble their PRS.

If anyone has some more, please add on.

Scott

[dray]

Thx for adding Scott, to be honest Ive posted this thread before and the mod keeps deleting it.. I ran through and made a simple setup from start to finish but didnt want to bother posting as the mods keep deleting my stuff..

If its up long enough Ill post start to finish.
Only took about 30 min to do a walk through.. Gotta love MS paint lol.

[bill.young]

There's a tech support bulletin with info on squaring the PRS tools (and ShopBots in general), and making sure they stay square between cutting sessions, at http://www.shopbottools.com/posts_%26_messages.htm

Bill

[terryd]

Just be aware that all sheet goods are not perfectly square especially MDF and melamine. Check the sheet first for diagonals. Just one more thing to look out for. These products are cut on the fly and the cutters are PLC controlled, very much like our 'bots'.

[dray]

You should never square your machine using sheet goods. Use a groove you cut on the machine. I consistantly get sheet goods that are out by up to 1/8"

[ted]

In this and another thread, concern has been expressed about the precision of the cuts on the ends of the main beam of new PRS tools. We value these comments and they have certainly led us to a new level of attentiveness with respect to the manufacture of the parts. It is not out of the realm of possibility that early in production a gantry beam slipped through our processing that was less square than it should have been.

Nonetheless, lest it seem we are more casual about the production of these beams than is the case, I’d like to provide a little detail about our enthusiasm for the engineering of the beams and our attention to the quality of their preparation.


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We spent a lot of time selecting the beam for the main gantry (X Car). It is a central component of the new PRS tools (a Bosch product; 200mmX100mm; 3 842 993 180). The extrusion is beautifully engineered and produced to high tolerances. It provides a 5X increase in stiffness over our earlier tools (deflection is .003 for 100# weight on a 48" tool) and offers excellent attachment base for the Y axis rails and drive system.

The US distributor of the extrusion cuts the beams to our specifications and tolerances on a sophisticated saw used only for this purpose. They also tap the channels for the 8 bolts at each end. The capability of this particular supplier figured prominently in our choice of product. Our tolerance for the cut ends of the beams is ~.05 degrees, or something like .010" across the 200mm face. And the supplier cuts, drills, and certifies the parts.


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The beams arrive for production at ShopBot in approximately 1-week supply batches in special-built crates. At ShopBot the cut angles on the beams are checked as they are loaded into our fixture for assembly with end plates and gussets.


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Because of concerns expressed about the beam cuts, we have been carefully evaluating the cuts of recent batches, quality check visits from the supplier are scheduled, and a local independent machine shop has been contracted for evaluation. In the last several weeks supplies, cuts on the beam have varied dimensionally by considerably less than the specs in most cases, and in a couple were right at spec. Thus, at least in terms of recent and current supplies of the beams, the angles are holding spec well. We have not noted any current problems with the square of the cuts.

An aspect of this issue that is important to highlight, is that the PRS carriage design is tolerant to some deviation from square in the beam and the end plate. It is the design function of the gusset to ultimately lock the car and beam into parallel with the surface of the table and square with the Y axis.

The gantry is fully assembled, squared, and aligned on a precision fixture built just for this purpose. It is then moved from the fixture to a pallet and shipping crate, blocked into position, and well protected. While it is, no doubt, possible for the gantry to get bumped around during shipping, we expect that most beams will arrive ready to set on the rails and put into action with little need or no need for adjustment. [For those interested, please review squaring document under Tech Support Posts on the main web site.]



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Ted Hall, ShopBot Tools