Good attitude!If I were building this pump for a business, to sell for profit, this set-back would be aggravating,...but I'm retired and building this little pump is just a part of my hobby which I do because I enjoy building "toys" and learning new things along the way. Before I built this pump, I had no idea that the adhesive forces of a "wetted surface" were so large,...that's just incredible!!
And now,....well now I get to design and build a check-valve assembly that has 9 intake valves, 9 output valves, and is as small and compact as I can make it. I do enjoy a challenge
Axial Swash Plate Feed Pump
- Thread starter Toymaker
- Start date
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A lot of detergents break down relatively easy, so your probably right about avoiding them.
I think you would see de-zincification before you saw the copper do anything.
How about this time around you share some build pics
You pull these wonderfully crafted devices out of apparently thin air like a magician. I for one would love to see some more swarf filled pictures.
Re-designed 9-piston axial pump:
This drawing is very crowded and I therefore elected not to show every little detail; cross section on the left does not perfectly match plan-view on the right. I also have not shown the location of alinement pins.
The valve head assembly consists of 3 aluminum plates; each one-way valve use a 6mm steel ball under light spring-loading fitted into a drilled hole. All valve head pieces will be made from 6061 aluminum. Green lines and circles are VMQ O-rings.
This design calls for the swash plate to rotate with the center shaft while the block holding the pistons is fixed and screwed to the valve head assembly.
Now that the drawings are mostly complete, swarf-filled pics (& video?) will soon follow
This drawing is very crowded and I therefore elected not to show every little detail; cross section on the left does not perfectly match plan-view on the right. I also have not shown the location of alinement pins.
The valve head assembly consists of 3 aluminum plates; each one-way valve use a 6mm steel ball under light spring-loading fitted into a drilled hole. All valve head pieces will be made from 6061 aluminum. Green lines and circles are VMQ O-rings.
This design calls for the swash plate to rotate with the center shaft while the block holding the pistons is fixed and screwed to the valve head assembly.
Now that the drawings are mostly complete, swarf-filled pics (& video?) will soon follow
Before I can cut any metal, I need a dimensioned drawing:
Yes, I've made long, ugly strands of swarf. This small piece of round 6063 aluminum stock will be the bearing cup shown in my last above post (#44). I much prefer using 6061 or even better, 7075, but those alloys are nearly impossible to get in Thailand.
The aluminum stock is mounted in a 4-jaw scroll chuck on my slant bed lathe. The chuck turns in the standard direction as a normal lathe, (CCW in the views above & below), but the cutting tools are mounted upside down because they're on the opposite side of the stock as compared to a normal lathe. The advantage of this arrangement is that most of the swarf is forced downward into the lathe's tray area, instead of upwards into the operator's face. Of course, cutting 6063 aluminum produces long, curly strands that defy gravity and go everywhere.
The video below shows the lathe under CNC control. Each cut is only 0.010" deep, and 0.6" long, and is repeated until the programed depth is reached.
With the first, larger diameter (1.691") completed, I've started machining down to the next the smaller diameter (1.376"). Once this is completed, I'll part (cut) the bearing cup section from the rest of the stock, flip the bearing cup around in the chuck and begin boring the holes for both the radial and thrust bearings, and finish the flange area.
TBC (To Be Continued)
The aluminum stock is mounted in a 4-jaw scroll chuck on my slant bed lathe. The chuck turns in the standard direction as a normal lathe, (CCW in the views above & below), but the cutting tools are mounted upside down because they're on the opposite side of the stock as compared to a normal lathe. The advantage of this arrangement is that most of the swarf is forced downward into the lathe's tray area, instead of upwards into the operator's face. Of course, cutting 6063 aluminum produces long, curly strands that defy gravity and go everywhere.
The video below shows the lathe under CNC control. Each cut is only 0.010" deep, and 0.6" long, and is repeated until the programed depth is reached.
With the first, larger diameter (1.691") completed, I've started machining down to the next the smaller diameter (1.376"). Once this is completed, I'll part (cut) the bearing cup section from the rest of the stock, flip the bearing cup around in the chuck and begin boring the holes for both the radial and thrust bearings, and finish the flange area.
TBC (To Be Continued)
THANK YOU!Yes, I've made long, ugly strands of swarf. This small piece of round 6063 aluminum stock will be the bearing cup shown in my last above post (#44). I much prefer using 6061 or even better, 7075, but those alloys are nearly impossible to get in Thailand.
View attachment 157623
The aluminum stock is mounted in a 4-jaw scroll chuck on my slant bed lathe. The chuck turns in the standard direction as a normal lathe, (CCW in the views above & below), but the cutting tools are mounted upside down because they're on the opposite side of the stock as compared to a normal lathe. The advantage of this arrangement is that most of the swarf is forced downward into the lathe's tray area, instead of upwards into the operator's face. Of course, cutting 6063 aluminum produces long, curly strands that defy gravity and go everywhere.
View attachment 157624
The video below shows the lathe under CNC control. Each cut is only 0.010" deep, and 0.6" long, and is repeated until the programed depth is reached.
View attachment 157625
With the first, larger diameter (1.691") completed, I've started machining down to the next the smaller diameter (1.376"). Once this is completed, I'll part (cut) the bearing cup section from the rest of the stock, flip the bearing cup around in the chuck and begin boring the holes for both the radial and thrust bearings, and finish the flange area.
View attachment 157627
TBC (To Be Continued)
More swarf!! I finished the bearing cap today. To insure a good, centered fit, I machined part of the cap such that it fits snuggly into the housing; I'm not sure if this feature has a name, but I've seen it used on many electric motors. The next video shows the the CNC lathe quickly making this feature.
Need to drill a hole through the cap large enough to fit my boring bar; first center drill a start point, then drill out the larger hole.
Moving over to the milling machine to drill 9 M4 holes through the cap's flange area. The first video shows the test run I often perform to re-assure myself that I've correctly modified the G-code use to position the holes.
Now that I'm convinced that holes are located correctly, I modify the G-code to have the CNC mill drill a little deeper,...enough to prevent the M4 drill from moving as it first starts to drill down. Ooops, seems that video is too large to post, so the next video shows the first two M4 holes being drilled. The red tube blows air onto the cutting tool, but as you can see in the video, the strands of 6063 aluminum simply whip the silicone tube around, so I pulled it back and out of the way off screen.
Pic below shows the finished cap with both bearings in place, and the last pic shows the cap screwed onto the housing.
TBC
Need to drill a hole through the cap large enough to fit my boring bar; first center drill a start point, then drill out the larger hole.
Moving over to the milling machine to drill 9 M4 holes through the cap's flange area. The first video shows the test run I often perform to re-assure myself that I've correctly modified the G-code use to position the holes.
Now that I'm convinced that holes are located correctly, I modify the G-code to have the CNC mill drill a little deeper,...enough to prevent the M4 drill from moving as it first starts to drill down. Ooops, seems that video is too large to post, so the next video shows the first two M4 holes being drilled. The red tube blows air onto the cutting tool, but as you can see in the video, the strands of 6063 aluminum simply whip the silicone tube around, so I pulled it back and out of the way off screen.
Pic below shows the finished cap with both bearings in place, and the last pic shows the cap screwed onto the housing.
TBC
It's fantastic how fast you can whip off parts with CNC. I only have manual machines.
Looking good!
Looking good!
The frame rate/drill bit speed in the last video is sorta funny. Looks like the bit is hammering in backwards lol.
Is that a ceramic thrust bearing?
Is that a ceramic thrust bearing?
The thrust bearing is a plain, garden variety stainless steel bearing. The redesigned housing should allow me to maintain an oil pool inside the housing, lubricating the bearings, swash plate, pistons, etc., separated from any pumped water buy O-ring seals. I may need to switch to different style piston seal, or perhaps use two O-ring seals on each piston to minimize water-oil mixing. Just another problem that may or may not occur.
Design by zen lol.
The last swashplate, how did you do the inclined plane? Did you just cut it on the cnc lathe?
The swash plate angle was machined on the milling machine. I clamped the round brass stock along the X axis, raised off the milling bed by a couple 0.060" aluminum sheets. A little right-triangle math gave the needed X & Y travel to cut the angle I wanted. Then it was just a matter of repeating the same angled cuts as I dropped Z 0.020" for each cut. You couldn't possibly use this procedure on a manual mill, but CNC makes such angled cuts as easy as milling a straight X or Y line for some given distance.
BTW, I'm re-using the swash plate from the first feed pump version.
In the previous feed pump design the swashplate was stationary and prevented from turning within the housing, and therefore didn't need to have a close fit around the steel shaft, so I drilled an over-size hole through the swashplate. However, the re-designed swashplate requires it to be turned by a stainless steel shaft, so I made a brass plug to fill the previously drilled hole, added 4 steel pins around the plug's circumference to keep the plug from ever rotating inside the plate, and added a 3mm keyway to allow the 8mm shaft to turn the swashplate. The flat, circular surface in the photo below sits on the thrust bearing which will aid in holding the steel locking pins in place should they ever work lose from their press fit and super glue.
That looks really solid.
Is the wear still going to be brass on brass?
Is the swash plate going to have seals on the shafts so it can be flooded with oil, or is it just going to be greased?
Neat seeing your process. Thanks for sharing.
Thanks !
Yes. Although it doesn't have much run time to date, the swash plate shows no signs of wear. That may change once the entire assembly is subjected to the forces of pumping pressurized water. I plan to do several tear-downs to examine parts for signs of excessive wear after I've managed to reach a few hundred PSI.
The drawing in post #43 shows the shaft seal next to the radial bearing, but not the seals between the piston block and housing, nor the O-ring seal on the closed end of the shaft. I believe oil will provide better lubrication to the slippers and ball joints than grease.
Good call on oil vs grease.
Besides lubrication it will help cool, flush debris, help the o rings seal and so on.
Besides lubrication it will help cool, flush debris, help the o rings seal and so on.
I finished machining the vale plate today; this part holds all 18 valve balls and their springs. I machined one surface on my lathe and then parted it off.
After drilling a mounting hole in the center of the disk, I bolted the plate onto my milling machine, and began drilling lots of 4mm diameter holes through the plate. I center-drill all holes before drilling with the 4mm drill bit. BTW, the center mounting hole will be plugged for final use.
Below is a video of the holes being peck-drilled, i.e., the mill is programed to drill 0.1" deep and then pop up to clear the swarf from the hole, then plunges down for another 0.1" cut. This is repeated until the hole depth is reached. I use a tooth brush help keep the drill bit free of swarf and to add a little oil to the drill bit.
After all the 4mm holes are drilled, I switch to an 8mm bit to open the holes where the 6mm steel valve balls will be placed.
The three holes being drilled below will be used to attach the brass block to the valve plate assembly.
Below pics show the finished valve plate front and back.
After drilling a mounting hole in the center of the disk, I bolted the plate onto my milling machine, and began drilling lots of 4mm diameter holes through the plate. I center-drill all holes before drilling with the 4mm drill bit. BTW, the center mounting hole will be plugged for final use.
Below is a video of the holes being peck-drilled, i.e., the mill is programed to drill 0.1" deep and then pop up to clear the swarf from the hole, then plunges down for another 0.1" cut. This is repeated until the hole depth is reached. I use a tooth brush help keep the drill bit free of swarf and to add a little oil to the drill bit.
After all the 4mm holes are drilled, I switch to an 8mm bit to open the holes where the 6mm steel valve balls will be placed.
The three holes being drilled below will be used to attach the brass block to the valve plate assembly.
Below pics show the finished valve plate front and back.
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I opened my axial pump CAD drawing on my computer this morning and while I was studying the next part to make, I suddenly realized that I wasn't quite finished with the valve plate; I hadn't yet drilled the cross-over holes which allow each piston to draw in fresh water. The red arrow in the drawing below shows the 4mm cross-over hole connecting the input water valve to the piston & cylinder.
I don't have an angle jig so I had to get creative to hold the plate at the angle I needed; below shows my solution. Looking into the two larger holes bottom left, you can see two holes have been drilled. I had to use an end mill as the drill bit wanted to wander.
Below you can see the end mill is through both holes.
This view shows the angle and how I used the slot in the mill table to hold the round plate.
I don't have an angle jig so I had to get creative to hold the plate at the angle I needed; below shows my solution. Looking into the two larger holes bottom left, you can see two holes have been drilled. I had to use an end mill as the drill bit wanted to wander.
Below you can see the end mill is through both holes.
This view shows the angle and how I used the slot in the mill table to hold the round plate.
Nice save!
Completed another part today. This 6082 aluminum ring serves to seal the piston-side of the water intake valve and holds the springs that push against the 6mm steel balls inside the valves. I've installed two O-rings and two springs to show how they fit onto the ring; I placed a single 6mm ball on top of one of the springs, again, only to show assembly position. Below is finished part.
Below video shows how the tiny spring recess's were milled out using a 1mm end mill. The recess is 0.045" deep and holds the springs in position to keep them from wandering about inside the valve chamber.
Last video shows the 1.5mm wide O-ring channels being milled using a 1mm end mill. To avoid breaking the end mill, milling depth was only 0.005" deep; 9 passes were needed to reach the 0.045" depth.
Below video shows how the tiny spring recess's were milled out using a 1mm end mill. The recess is 0.045" deep and holds the springs in position to keep them from wandering about inside the valve chamber.
Last video shows the 1.5mm wide O-ring channels being milled using a 1mm end mill. To avoid breaking the end mill, milling depth was only 0.005" deep; 9 passes were needed to reach the 0.045" depth.
