VP 785TF-W25-L56-N

VP 785TF-W25-L56-N

STIR ELEMENT, TUNING FORK, Two Encapsulated NdFeB Magnets, 48 MGO, High-Temperature Resin, 25mm Diameter, Used in Tubes

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STIR ELEMENT, TUNING FORK, Two Encapsulated NdFeB Magnets, 48 MGO, High-Temperature Resin, 25mm Diameter, 56mm Length, 80°C Max Operating Temp for Magnets

Shape

Tuning Fork

Container Used

Tubes

Tube/Vial Volume

50mL

Width

25mm

Length

56mm

Magnet Type

Neodymium (NdFeB)

Magnet Strength

48MGO

Temp Resistant

80°C Max Operating Temp

Autoclavable

Yes

Encapsulation/Coating

High-Temp Resin

No of Magnets

2

Magnet Dimensions

11.43mm x 0.69mm

Overview

The ability to make and use NdFeB stir elements to stir very viscous solutions and tightly couple them for high-speed mixing procedures has long been the goal of scientists. Also, the ability to use the flexibility of 3D printing to easily make Stir Elements of any shape is a significant advantage over the molding process typically used to encapsulate magnetic stirrers. The cost of making a mold is significantly high and the temperatures necessary to make the encapsulating material (like PTFE) molten is high enough to destroy the magnetic ability of NdFeB. The ability to 3D print and encapsulate NdFeB means that prototypes of a unique design can be made in a single day for less than $50.00, and if successful, the process can be automated for production runs of hundreds of parts per day.

In addition to the rare earth magnets NdFeB and SmCo, lesser expensive AlNiCo or Magnetic Stainless Steel can also be encapsulated by this method.

The Problems

Most Stir elements on the market today employ PTFE encapsulation via a molding process of AlNiCo or SmCo magnets. No company has been able to PTFE encapsulate NdFeB because the temperature necessary for melting the PTFE destroys the magnetic character of the NdFeB. NdFeB magnets are the strongest of all magnetic materials and therefore the most useful in mixing viscous liquids. Also, the strength of NdFeB stir elements is useful in high-speed stirring applications because they remain strongly coupled to the drive magnet. We were the first to produce PVDF and PEEK encapsulation of NdFeB stir elements. We developed a system of molding simple hollow cores from PVDF and PEEK and then placing a NdFeB magnetic cylinder into the hollow core and sonically welding the two cores together. This method works with simple cylinder designs but not with complex designs because of the limits of sonic welders.

We have also developed a vapor deposition process using Parylene to encapsulate NdFeB magnets that protects them from caustic solutions but the soft parylene coating is quickly worn off by the friction of stirring against a glass or plastic surface. We sought to protect the Parylene coating by taking a sheet of PTFE and using an end mill to make identical pockets on both side of the PTFE sheet leaving a 2 mm thick membrane of PTFE between the two pockets and placing a Parylene coated NdFeB disc into each of the pockets, so they are held in the pocket magnetically. This method protects the Parylene coating and allows for more complex stirrer designs, however cleaning these stir elements requires taking the parylene-coated NdFeB magnets out and cleaning the pockets and the parylene-coated magnets after each use to prevent cross-contamination. A cumbersome and time-consuming process.

The Solution

We start by making a stereolithography 3D printed stir element that has one or more slot openings in the top surface that will accommodate one or more magnets. Once the support structure is removed, the magnet(s) are placed into the slot or slots and a liquid form of the same high-temperature and chemically resistant resin is poured into the slot covering the magnet. The stir element is then placed into a UV light chamber to cure (harden) the resin and encapsulate the magnet. The Stir element is further hardened by placing in an oven at 80° C for 120 minutes. 3D stereolithography printing allows for many custom and complex designs, while still fully encapsulating the magnet. The ability to capture the utility of stereolithography 3D printing makes this method an inexpensive prototyping masterpiece. The resin formulation allows for traditional sterilizing methods, such as autoclaving and gamma radiation, to be used.

Advantages
  • Fully hard encapsulated NdFeB Stir Elements
  • Unlimited design possibilities due to stereolithography 3D printing
  • Solvent/Temperature resistance encapsulation material to 150°C
  • Rapid production of workable prototypes
  • Easy clean up
  • No need for coated magnets
  • Can use NdFeB N42 or NdFeB N52, SmCo, AlNiCo or Magnetic Stainless Steel

 

Applications

  • Stirring viscous solutions in unique vessel geometry where the stir element can be designed to fit the unique geometry and maximize stirring efficiency.
  • Provide maximum magnetic coupling with the drive magnet to effect high RPM stirring.
Solvent Testing

The High Temp 3D resin has been Solvent tested by the source of the resin and by V&P Scientific, Inc. and holds up very well against most common solvents except Chloroform and strong acids.  See the tables below and the testing protocols.

HIGH-TEMPERATURE RESIN SOLVENT COMPATIBILITY TABLE

V&P Scientific, Inc. Testing
The following table represents the difference between the initial measurements and weight compared to those after a 24-hour exposure to the solvents.

CHEMICALX(mm)Y(mm)Z(mm)vol (mm3)weight(g)vol(%)weight(%)pH
Acetonitrile0.050.010.039.280.000.880.00
10.00
Chloroform0.030.080.1324.750.032.362.384.5
Dimethyl Sulfoxide0.000.030.00
3.100.000.300.009.00
Dimethylformamide0.020.010.025.160.010.490.816.70
Ethyl Acetate0.010.020.036.270.010.590.816.50
Trifluoroacetic Acid0.02(0.28)0.03(23.14)(0.03)(2.20)(2.42)1.00
Experimental Protocol
  1. Prepare high-temperature resin cubes of dimensions 10mm x 10mm x 10mm
  2. Take measurements and the weight of the cube, first measure
  3. Using a 20mL glass vial, submerge the cube in 10mL of the desired chemical, tighten screw lid
  4. Wait 24 hours
  5. Dump chemical waste into a dedicated waste container
  6. Remove the resin cube and pat dry with a paper towel
  7. Take measurements and weight of the cube, second measure

 

Resin Supplier Testing
Percentage weight gain over 24 hours for a printed and post-cured 10mm x 10mm x 10mm cube immersed in the respective solvent.

CHEMICALvol(%) gainweight(%) gain
Acetic Acid, 5%<1<1
Acetone<1<1
Isopropyl Alcohol<1<1
Bleach 5%<1<1
Butyl Acetate<1<1
Diesel Fuel<1<1
Diethyl Glycol Monomethyl Ether<1<1
Hydraulic Oil<1<1
Skydrol 5<1<1
Hydrogen Peroxide (3%)<1<1
Isooctante (Gasoline)<1<1
Mineral Oil (Light)<1<1
Mineral Oil (Heavy)<1<1
Salt Water (3.5%) Nacl<1<1
Sodium Hydroxide<1<1
Water<1<1
Xyline<1<1
Hydrochloric Acid1.2<1

Related Products

Hydrophobic Coated vs Non-Coated Pin Transfers

Solid Pin Delivery Data For Aqueous Solutions In 96 Format With Uncoated And /Ah Hydrophobic Coated Pins
PinDescriptionnl TransferredCV%
0.229 mm diameter (FP9)Total PinUncoated7.412.4
Hydrophobic7.465.4
0.229 mm diameter (FP9)Hanging DropUncoatedN/AN/A
Hydrophobic2.093.8
0.457 mm diameter (FP1)Total PinUncoated33.483.2
Hydrophobic28.177.5
0.457 mm diameter (FP1)Hanging DropUncoated16.964.5
Hydrophobic8.510.8
0.787 mm diameter (FP3)Total PinUncoated87.323.9
Hydrophobic77.43.9
0.787 mm diameter (FP3)Hanging DropUncoated48.771.2
Hydrophobic43.059.4
1.19 mm diameter  (VP 409 & VP 386)Total PinUncoated247.222.8
Hydrophobic192.672.6
1.19 mm diameter (VP 409 & VP 386)Hanging DropUncoated76.351.6
Hydrophobic108.42.8
1.58 mm diameter (VP 408 & VP 384)Total PinUncoated273.54.6
Hydrophobic259.253.1
1.58 mm diameter (VP 408 & VP 384)Hanging DropUncoated201.935
Hydrophobic170.047.5

Transfer Of Horseradish Peroxidase In Tris Buffered Saline With Pin Tools

Conclusion

Coating pins will reduce the total amount of liquid transferred and also reduce the amount of non-specific binding to the stainless-steel pins. If the substance you are transferring has high non-specific binding this will be an important factor in selecting your pins.

Slot Pin Delivery Data For Aqueous Solutions In 96 Format With Uncoated And /Ah Hydrophobic Coated Pin
PinDescriptionnl TransferredCV%
0.229 mm diameter (FP9)Total PinUncoated7.412.4
Hydrophobic7.465.4
0.229 mm diameter (FP9)Hanging DropUncoatedN/AN/A
Hydrophobic2.093.8
0.457 mm diameter (FP1)Total PinUncoated33.483.2
Hydrophobic28.177.5
0.457 mm diameter (FP1)Hanging DropUncoated16.964.5
Hydrophobic8.510.8
0.787 mm diameter (FP3)Total PinUncoated87.323.9
Hydrophobic77.43.9
0.787 mm diameter (FP3)Hanging DropUncoated48.771.2
Hydrophobic43.059.4
1.19 mm diameter  (VP 409 & VP 386)Total PinUncoated247.222.8
Hydrophobic192.672.6
1.19 mm diameter (VP 409 & VP 386)Hanging DropUncoated76.351.6
Hydrophobic108.42.8
1.58 mm diameter (VP 408 & VP 384)Total PinUncoated273.54.6
Hydrophobic259.253.1
1.58 mm diameter (VP 408 & VP 384)Hanging DropUncoated201.935
Hydrophobic170.047.5

Transfer Of Horseradish Peroxidase In Tris Buffered Saline With Pin Tools

Conclusion

Although the slots in the pin are a precise volume, the liquid that is transferred is usually more. The reason for this is due to the surface tension of the liquid causing the liquid in the slot to “bow out” thus increasing the volume of the liquid in the slot. If is important for you to transfer exactly a certain volume we can make custom slots to match the surface tension characteristics of your liquid

Liquid Surface Tension

Effect Of DNA Or BSA Concentration On Slot Pin Transfers Of Uncoated And Hydrophobic Coated Pins (FP3CS500)
Solvent/SampleConcentrationCV%nl FITC TransferredCV%nl FITC Transferred
UncoatedUncoatedHydrophobic CoatedHydrophobic Coated
DMSO (-)08.1353.427.5298.72
DMSO + DNA (mg/ml)0.56.6497.216.6435.86
0.259432.494.1391.93
0.1258.9363.640.9344.75
0.06252.3381.862331.68
0.03131.5378.034.4331.71
0.01561.2357.521.4329.03
Tris (-)04.9577.317.2493.53
Tris + DNA (mg/ml)0.54.5540.531.1477.5
0.254.6518.216.1456.75
0.12515.8583.254.1438.82
0.06254.2551.173.1433.69
0.03134.4536.662.3458.37
0.01562.9528.531.2441.1
Tris + BSA (%)45.4462.1311409.27
14452.862.7426.58
0.2511.7456.451.3408.72
0.06251.1445.226.5393.07
0.01563.7462.853.9430.2
0.00391.5493.542.2437.29
0.0012.9504.250.7475.96
Conclusions

1. Increasing the concentration of DNA (sheared salmon sperm) to .25 mg/ml significantly increases the volume of DMSO liquid transferred for both coated and uncoated FP3S500 Slot Pins.
2. Increasing the concentration of DNA does not significantly increase the volume of Tris buffer (aqueous) transferred by both coated and uncoated FP3S500 Slot Pins.
3. Increasing the concentration of BSA (Bovine Serum Albumin) significantly decreases the volume of Tris buffer transferred by both coated and uncoated FP3S500 Slot Pins.
4. Hydrophobic coated FP3S500 Slot Pins transferred less DMSO – DNA and less Tris DNA and less Tris BSA than the uncoated FP3S500 Slot Pins.
5. Both coated and uncoated FP3S500 pins transfer significantly more aqueous solution than DMSO.

Effect Of DNA Or BSA Concentration On Slot Pin Transfers Of Uncoated And Hydrophobic Coated Pins (FP1CS50)
Solvent/SampleConcentrationCV%nl FITC TransferredCV%nl FITC Transferred
UncoatedUncoatedHydrophobic CoatedHydrophobic Coated
DMSO (-)04.249.382.149.31
DMSO + DNA (mg/ml)0.54.951.242.656.79
0.251.750.21.249.53
0.1251.551.272.349.77
0.06252.249.344.148.19
0.03131.249.030.250.23
0.01562.445.91.446.64
Tris (-)02.689.512.991.34
Tris + DNA (mg/ml)0.5777.110.684.62
0.253.982.221.684.89
0.1253.985.42185.08
0.06251.585.362.885.03
0.0313284.52388.19
0.01562.682.922.883.2
Conclusions

1. In contrast to the FP3S500 data, increasing the concentration of DNA to .25 mg/ml does not significantly increase the volume of DMSO liquid transferred for both coated and uncoated FP1S50 Slot Pins.
2. Increasing the concentration of DNA does not significantly increase the volume of Tris buffer (aqueous) transferred by both coated and uncoated FP1S50 Slot Pins.
3. In contrast to the FP3S500 data, FP1S50 coated pins transferred about the same volume of DNA at all concentrations as did uncoated pins.
4. Both coated and uncoated FP1S50 pins transfer significantly more aqueous solution than DMSO.
5. The differences between the FP3S500 and the FP1S50 pin may be due to the different pin diameter’s effect on contact angle and therefore on the “wetting” of the pin. See the diagram on the link to / ah energy system.

PinDescriptionnl TransferredCV%
0.229 mm diameter (FP9)Total PinUncoated7.412.4
Hydrophobic7.465.4
0.229 mm diameter (FP9)Hanging DropUncoatedN/AN/A
Hydrophobic2.093.8
0.457 mm diameter (FP1)Total PinUncoated33.483.2
Hydrophobic28.177.5
0.457 mm diameter (FP1)Hanging DropUncoated16.964.5
Hydrophobic8.510.8
0.787 mm diameter (FP3)Total PinUncoated87.323.9
Hydrophobic77.43.9
0.787 mm diameter (FP3)Hanging DropUncoated48.771.2
Hydrophobic43.059.4
1.19 mm diameter  (VP 409 & VP 386)Total PinUncoated247.222.8
Hydrophobic192.672.6
1.19 mm diameter (VP 409 & VP 386)Hanging DropUncoated76.351.6
Hydrophobic108.42.8
1.58 mm diameter (VP 408 & VP 384)Total PinUncoated273.54.6
Hydrophobic259.253.1
1.58 mm diameter (VP 408 & VP 384)Hanging DropUncoated201.935
Hydrophobic170.047.5

Aqueous Transfer with Solid Pins

Hydrophobic coating pins will reduce the total amount of aqueous HRP liquid transferred and also reduce the amount of non-specific binding to the stainless-steel pins. If the substance you are transferring has high non-specific binding this will be an important factor in selecting your pins.

 

Pin diameter also has an effect on the degree of reduction of liquid transfer with hydrophobic coating as the smaller the diameter the less the reduction of transfer. This is most likely due to the curvature of the pin affecting the wetting contact angle

PinDescriptionnl TransferredCV%
0.457 mm diameter (FP1)6 nl SlotTotal Pin*Uncoated25.610.8
HydrophobicN/AN/A
10 nl SlotTotal Pin*Uncoated23.366.1
Hydrophobic25.856.9
50 nl SlotTotal Pin*Uncoated67.832.5
HydrophobicN/AN/A
0.787 mm diameter (FP3)  100 nl SlotTotal Pin*Uncoated180.327.2
Hydrophobic205.845.5
200 nl SlotTotal Pin*Uncoated277.824.9
Hydrophobic287.33.8
500 nl SlotTotal Pin*Uncoated581.165.2
Hydrophobic555.693

DMSO Transfer with Slot Pins

Hydrophobic coating pins will slightly increase the total amount of DMSO FITC liquid transferred.

PinDescriptionnl TransferredCV%
0.787 mm diameter (FP3)    100 nl Slot Total Pin, Including SlotUncoated195.691.6
Hydrophobic170.22.9
0.787 mm diameter (FP3)  100 nl Slot, Slot OnlyUncoated149.674.9
Hydrophobic129.617.6
0.787 mm diameter (FP3)200 nl Slot Total Pin, Including SlotUncoated269.771.9
Hydrophobic228.6217.1
0.787 mm diameter (FP3)200 nl Slot, Slot OnlyUncoated237.528.9
Hydrophobic186.95.9

Aqueous Transfer with Slot Pins

Although the slots in the pin are a precise volume, the liquid that is transferred is usually more because of the volume carried on the sides of the pins. 

As seen with other aqueous data the amount transferred on hydrophobic coated Slot pins is less than on uncoated Solid or Slot pins. Thus Hydrophobic coating has the most effect on aqueous transfers.

Withdrawl Speeds Impact on Volume Transfer

Solid Pins More affected by Source Plate Volume

Volume Transferred For FP1 Pins (Uncoated) In 96 And 384 Formats
Volume Transferred For FP3 Pins (Uncoated) In 96 And 384 Formats

Note: Same volume (200ul for 96 Format and 74 ul for 384 Format) in recipient plates and same pin withdrawal speed for all pins. Changes to pin withdrawal speed or volume in the source plate can result in different volumes being transferred.

Transfer volumes should always be confirmed by customers for their assay conditions and automated system.

Aqueous Solutions Pin Transfer Volumes Ranges

Aqueous Solutions on Uncoated Pins in 96 Format Microplates(1)
Pin TypePin Diameter(mm)Shape96 Format Low Range(nL)²96 Format High Range(nL)²
FP90.229Solid1339
FP80.356Solid1537
FP10.457Solid2261
FP1S60.4576nL Slot3467
FP1S100.45710nL Slot3974
FP1S500.45750nL Slot90124
FP30.787Solid93213
FP3S1000.787100nL Slot213334
FP3S2000.787200nL Slot311449
FP3S5000.787500nL Slot515671
FP40.914Solid126289
Footnotes: (1) Delivery volume range is determined by speed of withdrawal from source liquid: Z-Speed Range = 1.5-30 mm/sec, slow speed = low volume delivery range, fast speed = high volume delivery range (2) 200ul source plate volume per well
Aqueous Solutions on Hydrophobic Pins in 96 Format Microplates(1)
Pin TypePin Diameter(mm)Shape96 Format Low Range(nL)²96 Format High Range(nL)²
FP90.229Solid1338
FP80.356Solid
FP10.457Solid2360
FP1S60.4576nL Slot3367
FP1S100.45710nL Slot4075
FP1S500.45750nL Slot86119
FP30.787Solid76209
FP3S1000.787100nL Slot188324
FP3S2000.787200nL Slot288436
FP3S5000.787500nL Slot473649
FP40.914Solid
Footnotes: (1) Delivery volume range is determined by speed of withdrawal from source liquid: Z-Speed Range = 1.5-30 mm/sec, slow speed = low volume delivery range, fast speed = high volume delivery range (2) 200ul source plate volume per well
Aqueous Solution on E-Clip, Uncoated Pins(1)
Pin TypePin Diameter(mm)ShapeLow Range(nL)²High Range(nL)²
FP1.58Solid Pointed175594
FPS.51.58500nL Slot524962
FPS1.581000nL Slot10561476
FPS21.582000nL Slot17392174
FPS51.585000nL Slot51504953
FP61.58Solid Flat465960
FP6S.51.58500nL Slot9341445
FP6S1.581000nL Slot13961930
FP6S21.582000nL Slot20722637
FP6S51.585000nL Slot48204693
Footnotes:(1) Delivery volume range is determined by speed of withdrawal from source liquid: Z-Speed Range = 1.5-30 mm/sec, slow speed = low volume delivery range, fast speed = high volume delivery range (2) 200ul source plate volume per well for 96 Format and 75ul source plate volume per well for 384 Format

DMSO Pin Transfer Volume Range Charts

Uncoated Pins in 96 and 384 Format Microplates(1)
Pin TypePin Diameter(mm)Shape96 Format Low Range(nL)²96 Format High Range(nL)²384 Format Low Range(nL)³384 Format High Range(nL)³
FP90.229Solid41038
FP80.35Solid1326618
FP10.457Solid18431131
FP1S60.4576nL Slot24491534
FP1S100.45710nL Slot30542140
FP1S200.45720nL Slot37612746
FP1S300.45730nL Slot46683554
FP1S400.45740nL Slot57784563
FP1S500.45750nL Slot70905675
FP30.787Solid671392979
FP40.91Solid941973498
FP3S1000.787100nL Slot175241114163
FP3S2000.787200nL Slot280332203250
FP3S5000.787500nL Slot535559427464
FP4S10000.911000nL Slot9401011704800
FP4S20000.912000nL Slot1518160812771362
Footnotes: (1) Delivery volume range is determined by speed of withdrawal from source liquid: Z-Speed Range = 1.5-30 mm/sec, slow speed = low volume delivery range, fast speed = high volume delivery range (2) 200ul source plate volume per well (3) 75ul source plate volume per well
Hydrophobic-coated Pins in 96 and 384 Format Microplates(1)
Pin TypePin Diameter (mm)Shape96 Format Low Range(nL)²96 Format High Range(nL)²384 Format Low Range(nL)³384 Format High Range(nL)³
FP9H0.229Solid41038
FP8H0.35Solid924617
FP1H0.457Solid1539927
FP1S6H0.4576nL Slot23491432
FP1S10H0.45710nL Slot29532038
FP1S20H0.45720nL Slot35592643
FP1S30H0.45730nL Slot47693553
FP1S40H0.45740nL Slot54754158
FP1S50H0.45750nL Slot69905773
FP3H0.787Solid671342776
FP4H0.91Solid9518932102
FP3S100H0.787100nL Slot170227108164
FP3S200H0.787200nL Slot266320190239
FP3S500H0.787500nL Slot520542416456
FP4S1000H0.911000nL Slot9321000741805
FP4S2000H0.912000nL Slot1571163813511423
Footnotes: (1) Delivery volume range is determined by speed of withdrawal from source liquid: Z-Speed Range = 1.5-30 mm/sec, slow speed = low volume delivery range, fast speed = high volume delivery range (2) 200ul source plate volume per well (3) 75ul source plate volume per well
E-Clip, Uncoated Pins, for 96 and 384 Format Microplates(1)
Pin TypeDiameter (mm)Shape96 Format Low Range(nL)²96 Format High Range(nL)²384 Format Low Range(nL)³384 Format High Range(nL)³
FP1.58Solid Pointed147411168395
FPS.51.58500nL Slot442704631843
FPS1.581000nL Slot893113013431498
FPS21.582000nL Slot1911203826072767
FPS51.585000nL Slot3908429651805253
FP61.58Solid Flat323674154398
FP6S.51.58500nL Slot73410428551053
FP6S1.581000nL Slot1210150016381717
FP6S21.582000nL Slot2299238427873068
FP6S51.585000nL Slot4329465652375245
Footnotes:(1) Delivery volume range is determined by speed of withdrawal from source liquid: Z-Speed Range = 1.5-30 mm/sec, slow speed = low volume delivery range, fast speed = high volume delivery range (2) 200ul source plate volume per well (3) 75ul source plate volume per well